[MarkGritter]

I would probably raise from the button. I don't understand why you say there were 5 players in the pot--- the blinds have not yet acted, so there are only 3 limpers ahead of you. It is generally worth trying to keep the blinds out. And you have three to a wheel, which is likely to have a small equity edge against three limpers. You would certainly play this hand against a raise.

The only reason to not raise here is to manipulate the pot size. This is not something you should be worrying about as a beginner. Your hand is strong enough to be betting for value.

Tossing the 7 is almost certainly correct here, although some might argue that the deck is sparse due to the number of players, so it is OK to play it. I think you want to be drawing very smooth in a multiway pot. You can reconsider if you get another 7 on the draw.

You don't have to improve to call a single bet here, particularly if you are closing the action. If there was a raise the first round the pot would be certainly large enough to take another card off. Even here you are getting 9:1. That's huge. You are about 40% to improve to a one-card draw when you draw two, and a bit less than 10% to draw two good cards. (Possibly less because of all the low cards that are already out there.)

In general you can take a card off whenever you had a legitimate starting hand, brick, and face only one bet. If you are stealing or defending there are situations where a fold is appropriate. But, if you always fold unimproved to a single bet the second round you are folding too often and your opponents can use that against you.