Very nice tanks.
Herpchat, you may want to try for something a little shorter in height as a feeding station, with something to hitch to. Lots of people use clam shells. Also, if you thaw the mysis in SW, they will sink when completely thawed. You may have to turn off the filtration systems to keep them from being blown out.
Your horses look like kuda, am I right? I think kuda are the same as reidi as far as baby needs, in that the babies will float for the first couple of months. If so, they will need a kreisel system set up to be successful in raising them. Basically, that is a set up where the babies cannot reach the top of the water to ingest air.
They are also born a little larger, so newly hatched BBS will be OK for the 1st few days, but will need to be grown out after that.
I'm sure you already know about it, but there is lots of good info on
www.seahorse.org.
DJC - very pretty tank. I've never had the prolifera or the stalky caulerpa (I think you are calling it feather) go sexual. (I'm looking at the top and 2nd pics - it's not feather, I just can't remember it's name right now. Too early and not enough caffeine) Are you keeping only females to prevent babies, or just can't find mates?
Also, the LFS around here regularly trade me frags or other types of caulerpa for my excess. I've got about a dozen different kinds. Maybe something to look into.
As far as the xenia - it won't hurt the horses or their babies - tho I can't think of any reason it should be in a baby tank, especially a kreisel set up. Most keepers have their babies in bare bottom tanks for ease of cleaning.
Good luck to both of you, and if you have any questions, just let me know.