I figured you'd be handling that, Katsu. I thought that went without saying.

I don't know about that last part - Attributes are ranked against our peer-groups in accordance with age and development. So, Pinnacle Attributes are only considered Pinnacle in relation to others of our age - and since we're only 13 years old, Superhuman Strength/Dexterity
might be roughly equivalent to the Attributes of an Average 16 year old ninja, and Pinnacle is that of an Above-Average one that age.
Comparatively, Skills are ranked independently of our body's actual age and development - the metrics used to measure Skill relate to our effectiveness, knowledge, and ability to apply what we know to those ends as a measure of our experience, familiarity and ingenuity.
It's a lot of XP either way. Pinnacle Strength provides improvement to a lot of different things, but the gains would be noticed as general uptick in a variety of fields. Elite Kenjutsu, on the other hand, is a far more noticeable and significant upgrade in effectiveness, albeit to a singular field.
And honestly, if we're gonna be upgrading Attributes to Pinnacle once we've gotten all three to Superhuman, it's likely going to be Dexterity > Constitution > Strength or Constitution > Dexterity > Strength. Because let's not forget that while Dexterity may help us dodge better and hit more accurately, it's Constitution that determines our stamina and tolerance for pain. Strength pales in importance to those two.
Still, that's a whiles away in the future.
¯\_(ツ)_/¯
I think the listed Skills are listed as relevant because they're used to help with working as a team to plan the party (Diplomacy) or noticing what the others are bringing so you don't bring the same thing and thus cover all the bases for party success (Perception).
So, either way, I think the listed Skills weren't "what success is based off of", so much as "what our approach is". Our success and failure is probably based on
how we used them and the levels for those Skills are probably just measures of how
much we succeed or fail based on our approach.
Fair enough, though I'm still of the opinion we leave that for growth via IC-Usage.
Hozuki Suigetsu's Hydrification technisue isn't a Water-Natured Henge at all. I mean, it seems pretty similar, but the methodologies appear to be vastly different.
The Henge involves constant emission of chakra to disguise yourself as a person/plant/object. Basically, you're still solid matter, and it required focus to keep up.
The Hydrification technique is a Hiden Ninjutsu and the secret of the Hozuki Clan of Kirigakure. It's part of what made Hozuki Gengetsu -
the Second Mizukage - so goddamn terrifying in battle. It appeared to involve using Water-Release chakra to super-saturate parts of the body until they took on the properties of liquids while still maintaining cohesion - this didn't seem to require much focus at all (though that might just be because our examples are Jonin or a Kage). They could also manipulate their liquid-bodies with impunity via Water-Release, so that's a thing...
I imagine the shinobi who invented the Hydrification jutsu were
completely insane and the experimentation involved with creating it
had to have mutilated tons of people in the process.
I
highly doubt we'll be able to engineer a technique like Hydrification just from combining Nature Transformation with one of the Academy Three at Master level...
Well, that's B-Rank Cooperation Ninjutsu, and the amalgamation has two heads - ergo, two brains. It's also not categorized as Yang-Release, though...
Still, the DBZ fusion
does involve gestalt mental functions because it allows both minds and personalities to merge and create a new persona formed from the two participants. So... Yin-Release would
have to be involved because Yang Release doesn't involve the mind. Yang is related to Life energy, and Yin is related to Spiritual energy.
1 - I don't actually know. I think the Quest Rewards were simply proficiency with the musical instruments used and XP to the Social Skills and Attributes used. We certainly don't have a Perk for it... though with Katsuragi around, we probably will have one by the end of the month.
2 - Given they're immaterial and cannot talk or interact with objects... That'd be a little weird. I mean, we've already proven we can make a bunch of clones and have them transform into disguises and act ins simple, pre-programmed ways. But I doubt enough to make it an actual part.
3 - That's a great idea actually, but I don't know where we'd get that stuff on short-notice. Not to mention that means more to clean up afterwards. Hmn... Maybe we could have our Henged Clones are makeshift decorations? It'd be a ridiculous, frivolous waste of chakra, but it just might work...