legacies

Fraternities, yes. I'd auto invite a kid to stuff if he was a legacy and give him a good chance. Course, it isn't an auto bid. If the kid isn't right for your fraternity then legacy or no he shouldn't get a bid. Being a legacy is great, but like if you're kind of a nerd don't go SAE just because your dad was one, go Sig Nu. It's more about your happiness than about getting in, you may get in somewhere because of your dad but do you really want to be there if that's not you? Sororities I think it matters but less so given that (as far as I know) more legacies rush.

Yes, it does help but to a certain degree. Ultimately it's up to whether or not you're a good fit for the chapter or whether the chapter is a good fit for you.