feeding them really isn't a problem as long as you can find some that will eat frozen food. they should be fed twice a day, like maybe 6 frozen mysis, enriched of course. there should also be one day a week for fasting. live food should be offered at least once a month. they love ghost shrimp! as do the pipefishes.
there are some other fish you can keep with them, like the banggai cardinals and some gobies, but if you're going to do that make sure you introduce the seahorses before the other fish.
i think you should decide whether you're going to do a seahorse tank or not before you buy the actual equipment because there are things to take into consideration. for example, height is more important to them than width. especially if you get a pair, they need lots of height to perform their mating dance! minimum height should be 18". they also don't like a strong current, so you don't want to stick them in a tank with like 4 powerheads.
hope that helps some. =)