What can we start off with?
Nothing. You start off with not a single copper to your name.
Can they be unlimited level 0 casting?
Not if they cause damage. Only non-damaging spells may be cast at an unlimited amount.
When do we gain new feats?
Every other level. (1,3,5,7,9…)
What will the EXP system be like?
The EXP will be class level x 100. So at Level 1 in order to get to Level 2 you would have to earn 100 EXP. At Level 2 it would be 200, and so on. Earning EXP depends on monsters, the average monster will probably get you around 10-20 points, but boss battles can be around 30-50
Game Play Style?
There will be many chances to fight and talk. You will be unraveling mysteries and trying to save a kingdom.
Gaining Ability Scores
Characters will gain +1 to any ability score of their choice every five levels (5, 10, 15, etc)
Starting Skill Points
3/4 the skill points as listed in 3.5 book and online surfaces.
So if the online guide tells you a Level 2 rogue gets 12 skill points you would only get 9.