Personally, I doubt that Charms and free Transfiguration are alike in that sense, but even if they are we have Word of McGonagall that it's possible to Transfigure just your skin or hair. Apparently human bodies are subdivided, according to the idea of Forms.

IIRC, neither Quirrell nor Dumbledore have pre-cast shields in TSPE, which (IIRC) is the only piece of serious action by competent people in MoR.

Funny thing about the combat in TSPE, we get this little digression:

The Auror was protected by a blue shimmer, it was hard to see the details but Harry could see that much, the Auror had shields already raised and strengthened.

Crap, thought Harry. According to the Defense Professor, the essential art of dueling consisted of trying to put up defenses that would block whatever someone was likely to throw at you, while trying in turn to attack in ways that were likely to go past their current set of defenses. And by far the easiest way to win any sort of real fight - Professor Quirrell had said this over and over - was to shoot the enemy before they raised a shield in the first place, either from behind or from close enough range that they couldn't dodge or counter in time.

And a little later,

Bahry had already swapped the harmonics on his shields so that his own stunner couldn't pass back through, already tilted his wand back into a defensive position, already raised his hardened artificial hand into position to block anything blockable, and was already thinking wordless spells to put more layers on his shields -

The man wasn't looking at Bahry. Instead he was poking curiously at Bahry's stunner where it still wavered on the end of his wand, drawing out red sparks and flicking them away with his fingers, slowly disassembling the hex like a child's rod puzzle.

The man hadn't raised any shields of his own.

Quirrell (and presumably Dumbledore) are on the level above where they have to worry about shielding against anyone but an equal.

And do I really have to go back through Self-Actualization and come up with the list of times the bullies and Tonks had pre-cast Protegos before they entered combat?

I don't remember canon well, but I would have noticed consistent pre-cast shields.

Yes, this is a change from canon. Mainly because magical combat was actually given some thought in MoR.

This is the same idea as hover charm.

Except a lot faster and with less expenditure of energy. Rather than bouncing someone off the ceiling- which seems difficult to do hard enough to instantly kill a wizard (who can survive a lot more blunt trauma than Muggles)- you just rip their brain out their eyesockets.

Imperio can be resisted.

As far as I know, the only word on that we have in MoR is "Powerful wizards are not so easy to Imperius," which leaves a lot of room for interpretation.