My family and I are headed to Galveston this week and I was wondering what kinds of sharks I could expect to catch in the surf. I am not planning on kayaking baits out and am hoping to catch 5' or smaller.
(Any tips or tricks would be appreciated too.)

Bonnets, Hammers, Black tips. In the surf, they will be 14" and up.

Which ones may I eat?

Check your TPWD handbook for that information. Get familiar with the Sharks you will most likely encounter. There is subtle differences that you need to be familiar with. To someone who is new to the salt they would probably mistake a black tip with a spinner or the other way around. The spinner has black markings on the anal fin which the black tip does not. I've been shark fishing for several years and I've yet to keep one simply because there is way better fish to keep and eat. But that's my opinion. Good luck to you, hope this storm don't send them out to deeper water.