I'd agree except that unless I'm misremembering, or Da Vinci was very sneaky sneaky and has backups that Marie doesn't know about which is a distinct possibility, Marie deleted all of her recorded viewing of Taylor's exploits in Sheba in order to leave no proof behind. Which is probably why Taylor didn't get a bomb planted inside her Coffin, because if Lev had access to that knowledge he would absolutely have made sure to kill Taylor. And he certainly wouldn't have let her leave alive from Fuyuki.
But don't forget Contessa's message. Save her life and get the strongest Master, or save her body and get a catalyst for the strongest Servant.
But Taylor is alive, so logically any Servant she summons without an Catalyst has the potential to be an alternate version of her, like Skitter, Weaver and even Khepri.
And the Throne of Heroes is not connected with the timeline, so the fact that Taylor is still alive should not prevent her from summoning one of those.
Even more, Earth Bet could be considered a Lostbelt, and alternates of Taylor could be Lostbelt Servants. And Those are seriously above average compared to those of Proper Human History (or is that only in their own Lostbelt?)
And considering the events of Ward, wouldn't Khepri get some kind of Fame Boost?
Even think what possible Classes Servant Taylor could be:
Shielder: That one is for Mash... But considering she went out of her way to protect the people of her territory? And what she did to try and stop Zion? She should qualify from that effort alone.
Saber: Doubtful, since she definitely doesn't really have the Knight personality. She did have a Nanothorn Knife at some point, so maybe that qualifies?
Archer: She prefered to fight from a distance. It is not her fault that she ended up in close combat far to often. And considering the weird things Archers can fire, a Servant capable of shooting insects isn't that weird... Santa Altera shoots sheep, and Summer Jeanne shoots dolphins... Oh, and the typical Independant Action is a good fit as well...
Lancer: Battle Continuation. Nuff said. And she did wield Armsmaster's halberd when going one-on-one with Leviathan.
Rider: Didn't she have a giant bug to ride on called Atlas?
Caster: With her bugs she made Spidersilk costumes, and those were of rather impressive quality. That is enough to get the Item Construction skill. And she is pretty mucht omniscient in her territory, thanks to her bugs. That should count for Territory Creation.
Assassin: Well, she did try to fight ranged and unseen, and she spent quite a lot of her time as a cape trying to make sure certain people died. And considering what she did to Lung on their first meeting? (It was still Armsmasters fault...)
Berserker: She is a parahuman, and a natural trigger. All of those are slightly insane by definition. And considering what happened to her as Khepri? Definitely qualifies.
Ruler: Khepri. If she doesn't qualify as a Ruler, then they should hav named the Class differently.
Avenger: Khepri. She did bully Zion to death... And that is definitely revenge for all he did during Glod Morning.
Moon Cancer: This is supposed to be a BB-only class. But is Jinako possessed by Ganesha counts, then the Taylor & QA has to count as well.
Alter Ego: Near the end Taylor and QA were so linked neither could tell where one ended and the other began. So Queen Administrator should qualify as this Class.
Foreigner: She did have a link with an Alien in her head. OK, She is probably closer to MHXX, MIXA and Voyager than to the typical Lovecraft-types, but still...
Beast: Like Foreigner, she did have a link with an Alien in her head. If the Alien God can be a Beast, then so can Taylor & QA. Especially with the Fame Bonus Khepri should get from Earth Bet.
So, IMHO, any alternate of Taylor can be pretty much any Class. Even if some of them are pretty much a stretch...