1) Kind of. All of today's Canon DSLRs are compatible with EF mount lenses but only the crop-frame sensor bodies (****D, ***D, **D and 7D) support the EF-S lenses.
2) Generally yes, both in terms of optics and speed but you'll have to open your wallet for it.
3) There are still plenty of photographers who either appreciate film or passionately despise digital photography so there is definitely a market for your gear. The 75-300mm lens will probably bring in the most money though I don't imagine you'll get much more than $250 US for the lot though if the lenses are in pristine condition with boxes and manuals like the body, they could fetch a little more.