This is a lengthy post but I hope it answers your questions. I also included some links you might want to read.
The Witcher 1 was also 35. I seem to recall an interview where they said The Witcher 3 will be higher (though I don't have a source.) I think they said around 60?
I imagine so. I know for a fact they said in a recent interview that there are now 4 skill trees. Alchemy, Signs, Swordsmanship, and General Upgrades. I believe the general upgrades are different from the miniature "tutorial tree" they had in TW2.
In the
press handout from E3 2013 they said every skill in the skill-tree would have a visible effect on combat. In other words... they're trying to make it like a true action game where upgrades change your animations and speed up frames.
Since TW3 is a lengthier game, I expect they will have some kind of respec option.
I imagine so. Isn't this the way most story-driven RPGs do things? I think it's how TW1 did it...
I assume so. The alternative is making items require progressively rarer materials the more powerful they get.
You mean invulnerability frame? I have no idea. TW3 uses an actual dodge mechanic if that's what you mean. Here is what someone wrote about dodging in a
recent gameplay preview.