Shortest answer on seahorses is that they require a species specific tank...meaning no other fish. The reason (and this is all from research not experience) is that seahorses are extremely slow moving - which means if you have other faster fish they'll steal all the food before the horses can eat. I've heard that they CAN work with pipefish, and some other small, slow movine fish...but all around I'd guess it'd be better off to go just seahorses.
in addition, while you CAN do some corals I don't know that I'd recommend it - simply put seahorses use their tails to anchor to stuff, and this can and will damage sensitive corals.
Some cool, interesting stuff. I think the kudas are beautiful, and the fact that they're tank bred is a nice bonus.