1) Well, it all depends. With landing legs, probably. With a heatsheild, yes, the heatsheild will absorb the impact. Anything else, don't be so certain.
2) The best way is probably to use Seperatrons. I'm pretty sure no mod has that, but HGR Rocket Parts might.
3) Again, not sure, you would have to do some searching, but from what I know, no, there isn't a mod like that.
Fly safe!