Hmmm. Curious as to why it is costing you hundred dollars for a pair. Sites like seahorsesource.com and dracomarine.com sell captive bred aquacutlure seahorses for much less then that. IMO these type of CB aquacultured seahorses are the best available on the market.
Buying WC pairs of seahorses for large sums of money is ridiculous IMO. Not only do you have no idea how old they are, but IME many WC's never take to frozen food and you will have to continue to feed live food daily. IME the live foods cost around $600 per year per horse. WC seahorses also have to be treated prophylatically for paraistes with prazipro and fenbedazole, which is a pain. Better product and value to buy an aquacultured CB seahorse.
I tried a clown fish (CB false perc) with my WC reidi pair. They were fine together for awhile but I had to remove the clown fish for aggression issues. JMO.
I have kept many corals with my seahorses and know many succsessful keepers who keep corals and seahorses together. There are some restriction but many choices. I stay away from the SPS and seahorses because the seahorses will irritate the SPS corals, but in the wild reidi are often found living in SPS colonies.
Some of my personal favorite corals to mix with seahorses that are fairly easy are:
leathers (all types)
sponges (if you can get a good one)
ricordia's
mushrooms (none of the kind that can eat fish)
xenia's (any of the family, I have a soft spot for the pulsers)
clove polyps
zoanathid's
I think you will find quite a large variety of seahorse friendly corals.
Good Luck.