Playing this hand even on the BTN for value multiway is a bit iffy, but only because of the relatively short stacks most villains have for a 2/2/5 game. Your main component is the nut flush draw, which doesn't hit often, and 55 will hit a good flop very rarely (588 is not one of them). With this many players in the pot you won't be able to steal very often, so going for pure value seems reasonable. Ideally I'd like villains to play deeper, allowing for better implied odds, but I'm not terribly hating PRE as played either.
On the flop you have a trouble hand. The only hands you beat and will get action from are not far behind, and you could already be drawing (nearly) dead. The good thing is you have position, and are therefore better able to control the size of the pot. Checking behind is a valid option, let someone hit a straight and extract a little value later. Betting is ok too, but mostly to rep a steal in position, so I would bet small ($10-$12 range).
As played, on the turn I'm never potting. A half pot bet will accomplish the same that potting would, and you can safely fold to a raise. Note that charging max from a naked 8 is not that important, because a lot of the time we are already beat. Checking back turn is ok too, and you could still fold a lot of the times villain leads the river because now his range is 8xxx and he'd likely check a naked 8 there.