2) Skills only need to be unlocked (learned) once for both characters to be able to put points into it? Ie: if the DK reads a book that unlocks the identify skill, my other char can also put points in that skill - Is that correct?
That is correct, if you unlock a skill, both chars can put points into it.
3) Looking at some skills, like the one-handed weapon ones, it seems that putting one point into the skill shows 0 for its effect, and you only get an actual effect after 2 points. Is this correct? It seems that given you get so few skill points with so many things to spend them on, that this is rather a painful proposition.
No, it should show something like "0 (+ xx)" where xx is the effect of the bonus. If you add 1 point to critical hit for a weapon, it should look like "0 (+ 2%)". It does to me, at least.
4) Is there any way to get more skillpoints besides leveling up? (Ie: magic potions or books?)
I haven't found any, but then, I'm only just gotten through the first battlefield.
5) If I put points in, say, the 1-hand slashing skill - Do I have to specifically select that skill somehow for it to be used, or will it automatically give its bonuses if I use a 1-handed weapon?
Nope, those skills are passive.
6) I started with a DK warrior and hero survivor. I'd like to develop the hero starting as an archer but migrate towards being a strong mage by mid-late game. Will all the mage skills/abilities be available to the hero (assuming I assign attribute points wisely) even if he started as a survivor?
Given that you unlock the needed skill paths, absolutely. You can pretty much start out as a tank and switch to a mage, if that suits your fancy, all you have to do is allocate your stat points wisely and then buy back your skill points and redistribute them.
7) What are the most/least useful skills? Is there any good threads here discussing this?
Most useful is sharpen, I guess. It is completely insane, as it allows tiny fast attacking weapons to do as much or more damage than great swords. Least useful is lockpick, as it apparently doesn't work.
