Steverooo said:
You mentioned Multiclass characters; how are these handled, with respect to saves, primes, etc.?
I am not sure, as the rules for multiclass characters are not included in the box set, but I think that you need to have whatever primes your classes require (e.g. a Wizard/Rogue would need to choose Int and Dex for Primes -- thus having no "bonus" prime, unless a human).
Steverooo said:
In a game with no AoOs, feats, etc., is everyone able to strike unarmed like a monk, disarm, trip, etc., or are there no rules for this?
There are basic rules for unarmed combat in the box set, but they are such that any "boxer" or (nongiant) "wrestler" would likely be sliced and diced by a swordsman. The monks will have special unarmed combat abilities, but I don't know the details, as the monk class was not included in the box set.
Steverooo said:
How do races differ? Do Elves, for instance, have resistance or immunity to Sleep and/or Charm?
The races differ in ways similar to the D&D tradition (yes, elves are resistant to sleep, etc.). There are no big surprises here -- if you are familiar with the "elf" from any edition, you will find the C&C races familiar.
Unlike pre-3.x versions of D&D, though, humans are "balanced" with nonhumans (by getting an additional prime).
Steverooo said:
How are Stats determined?
Any way you want!

Choose your favourite D&D system (3d6, point system, etc) and go with it.
Steverooo said:
What about weapon, armor, and shield proficiencies?
By class (and fighters can choose to specialize in a particular weapon). There may be options for more customization in the full rules. In any case, it should be easy to fiddle with this to suit your needs.
Steverooo said:
Has Rope Use been removed from the game? If so, how is throwing a grapnel handled? With BAB?
Don't know about this!
Remember: my playtest was based on the box set rules alone! The full rules still have not been published.
Hope that helps.
