The flat bullhead would probly be yer best bet, IMO, IIRC they stay smaller than either the brown or yellow (9"-12" vs. 14"+). Likewise, bluegills are a little beefier than either of the other two, so I'd steer away there.
Kinda unclear from yer post, do ya have a pond? If ya have a pond ya could move 'em to, ya could grow 'em out in the 55 and move 'em to the pond later. For a long term permanent home a 55 is a little small for any of those fish, IMO.
Do ya have access to orange spotted sunfish? IMO, they are the prettiest of the sunfish and generally don't get much larger than 4" or so. Throw in a coupla native madtom catfish (don't have any idea what species are native to MS) and ya have a similarly themed tank on a smaller scale, with fish that will be able to stay housed in a 55 for their natural lifespan. Might take a little more effort to collect the fish, but it would be fun doin' so.
WYite