...well, that's likely to end up with the Grail interfering. Continue the attempt if you wish, but it may not go as you hope.
@justinkal @AnonymousRabbit @The-Chained-One @Nottheunmaker @BookMouse @PurposefulZephyr @reborn214
QM gave us the above warning about Dioscuri, might wanna re-evaluate that vote. Also:
Also, side note, your family doesn't have open access to that shed anymore; after maxing the financial damage track, the house had to be sold, and your family is living out of an apartment in Fuyuki. You can still go and summon there, but you'll have to get in, summon, and get out before the new residents wake up.
Not much point in directing children to break into someone else's property and hope the flashing lights and noise of the summon goes unnoticed. Better to find a different place with enough magical energy in the air to summon a Servant successfully.
Honestly, Nobu is a pretty poor choice.
The anti-mystery stuff is neat, but it isn't actually a super strong effect.
And more importantly, her personality will be really problematic for this situation.
Someone like Raikou, Kintoki, or Yoshitsune (aka Ushiwakamaru) is probably a better choice.
The problem with those three is that AFAIK they get completely fucked by Gate of Babylon. Gil can sit around all day as they fail to get through the hail of weapons. On temperament alone those three are fantastic (Raikou goes mom mode, Kintoki is all about defending kids and the innocent, and Ushi is completely loyal to the wishes of her summoner despite her savagery to all others) but IMO none of them can take on Gil and win. At the very least none of them have better odds than Artoria, who is the "safest" choice in that we know she "can" defeat Gil and give up the Grail. Sadly we don't know how likely it is that she'll do so, it took some serious personal changes in the Fate route but there she didn't know the Grail was corrupt for the majority of the route. In UBW she doesn't change nearly as much on a personal level but still accepts and faces the Grail's corruption before willingly destroying it.
Bluntly, none of the servants you mentioned are in the running because they don't really have a shot at beating Gil IMO. The main points to consider in regards to which Servant to give our kids is as follows, in no particular order:
1. Is it possible to summon them?
It's all well and good to say we'll summon Enkidu, Arjuna, or *cough*Dioscuri*cough* but it doesn't matter if they aren't Japanese or the one stated exception. Trying to summon with constellations as Catalysts is almost worse than using nothing, we're just as liable to get someone random like Orion as we are Castor and Pollux, assuming it works at all and we can "use" the constellations from so far away! I'll grant that Orion isn't a weak Servant either, but the problem THERE becomes the explicit warning the QM gave about the grail fucking with the summoning process of C&P. It wasn't explicitly stated why, if it was due to an attempt to summon a Divine Spirit, if it was because of the unreliability of star catalysts, or something else, but there's not much point in speculation if we know there will be attempts at fuckery. Cool idea, would love it if it worked, but by WoG the execution is liable to fall apart. I don't want to take the chance we get someone weak and almost unknown like Cassiopeia (who's whole "legend" is her bragging pissing off Poseidon, her daughter Andromeda being sent out as a sacrifice to appease said god, and then Cassiopeia being tortured to appease Poseidon after Perseus freed Andromeda). Granted, I don't think she'd be applicable to be summoned, I think it's more likely the summoning just fails and our kids have to try again and summon someone without us (if they can). Either way the result is undesirable, I don't like these odds.
2. Can they defeat Gilgamesh?
There is only one Servant who we know for sure will be in the next Grail War, and he's the big bad elephant in the room. To win the war Gil has to go down, otherwise he'll actively choose to set off the Grail. Rin is dead and we can't rely on some rando getting the pendant and choosing to summon with it over a historical catalyst, meaning no EMIYA to face Gil or teach Shirou. If Gil is going to be brought down, our Servant will have to be ready and able to do the deed. Raikou is not weak, but she has no counter to the Gate of Babylon that would allow her to rush and blitz Gil. If she got in close she would probably kick his ass but to me it seems almost certain that she'll be pincushioned or Ea'd first. Similar deal with Kintoki and Ushi, every situation I can think of involves them being riddled with holes. They're all straightforward servants like Artoria, but unlike her they don't have Excaliblasts to counter Ea or Avalon to defend and move in for a definitive strike. There may be other Servants who could potentially get past the GoB, like Nagao Kagetora and her skill "Armor is on the Chest" which causes an effect similar to reality warping to ensure projectiles miss her unless ". . . the shooting is done with enough aggression, to the point where she believes the possibility of her getting hit, the protection could be penetrated." The problem THERE is that I'm not confident in her ability to overwhelm and kill Gil quickly enough, his standard technique is literally to just increase his rate of fire. Nobu could temporarily stall Gil's rate of fire with her own, then if she used it quickly enough she could kill him with her "Demon King of Sixth Heaven" Noble Phantasm. It's a Reality Marble wherein Nobu weakens and burns away at Divinity and Mystery (depending on how much there is) potentially to the point of evaporation. Considering the combined amount of those two Gil has it's plausible he gets burned away into nothing before he can Ea the RM out of existence.
3. Can they be trusted?
If the Servant is one that is explicitly fighting for the wish of the Grail, how trustworthy they are depends on whether or not they believe that the Grail is corrupt and if they value their wish or their morals more. Cu for example doesn't give a damn about the wish and will obey almost any command. Nobu and Artoria both have problems here. Despite ostensibly being Lawful Neutral, Nobu is infamous for her sporadic I-don't-give-a-fuck behaviour. She has no direct wish, but isn't actually "good" and might care less about the Grail spitting out evil and more about showing off what a badass she is by defeating other servants and winning. With Artoria, the only real reason NOT to summon her is here. Do we trust her sense of right and wrong towards the people of the modern era more than we believe in her lust for a wish?
Damn, putting it like that I've convinced myself into changing my vote. Artoria is very determined for her wish, but she explicitly refuses to sacrifice innocent lives in the process. Killing a magus who got involved (even a shitty one that did it by accident like Shirou) is one thing, but if she was really as fanatical towards her wish as we're acting then she'd have been perfectly willing to prey on the people of the city for more power . . . which she avoids. She even praises Shirou for his unwillingness to consider it for even a moment, despite the crippling lack of mana leaving her at her weakest. Yeah, I think I trust Seibah. We don't have to convince her that her wish is wrong and that she should live for herself, we just have to ensure she knows the corruption is a certainty and she'll do the right thing and help.
Hearing this i think our best shot is artoria, we'll have to make sure the kids explain in detail just why the grail is a bad thing to use, but that's the only bad part and it's not that much of an issue.
Artoria is unironically one of our best bets here, simply because we know she
can win this fight. Especially with the massive power influx for more Excaliblasts and better stats. Summoning her is less a gamble on the victory (that's always a gamble but again here we definitively know she can pull it off) and more a gamble on mentality, which I think is a sucker's bet now that I'm carefully thinking about it and not just getting swept up in Kiritsugu's paranoia. I can't speak as much for her characterization in Zero, but in the VN she was totally cool with destroying the Grail when she knew for sure it was corrupt. AFAIK in Zero she never learns about the corruption, is it any wonder Kiritsugu can only see her as a fanatic desperate for her wish? She's ultimately a strong, good person. We can trust her to help, and we can trust that she CAN win. Here's hoping the post-game dice rolls go well.
What is angelform exactly?
The name of the account which made the only current vote for Artoria, one that involves breaking into the shed we no longer own. If we're sticking with Artoria the park should be fine, its the only place rich in mana from the leylines I can think of that we can quickly and easily access without complications. Besides, Salter shouldn't actually be possible to be summoned. Even if that does happen, that version of Salter (by summons and not Grail mud corruption) shares the same ideals as normal Artoria at heart. She downright
approves of her Master fighting to save the world, of facing "repulsive enemies and the more powerful adversaries." She's also just as happy to train her Master as vanilla Artoria, she's just more caustic in how she speaks and goes about these things. She's still Artoria, in the end.
[X] Plan Trust Seibah
-[X] Aim for a specific class: Saber
-[X] Aim for a specific Heroic Spirit: Artoria Pendragon
-[X] Change the summoning location to somewhere other than the cursed park: N/A
Any last words (Choose one)?
[X] Path of Family, which kept getting ripped away from you.
To whom (Choose one)?
[X] Fate, Illya, and Shirou