Actually it is not recommended to mix pipes and sea horses. You can mix them with passive fish like clown gobies, fire fish and a few others.
I would suggest doing a lot of reading on setting up a sea horse specific tank. Things you want to consider are :
the tanks tend to get dirtier due to the eating and pooping habits of the pony
lower flow than a regular reef tank
much lower temp than a regular reef tank 72-74 to keep illness at bay.
nothing in the tank that the ponies can hitch on that will hurt them - covering heaters or using a sump ect....
and you will need at the very least a 29 gallon ( not the self contained ones, unless you plan on a chiller - it's not unusual for these tank to run at 83 degrees) to house the ponies you listed.
seahorse.org has some excellent information on these wonderful creatures