WOW!!!! Good Luck. Must have $$ to burn and a very understandable wife.
Sounds like a great system.
For your seahorse tank , depending on where you place your power heads and size of power heads, you could use small pcs of eggcrate glued or zap strapped together to box off the intakes of the pumps so the horses don't get sucked up. It's a little gaudy looking but works well.
Anyhow have fun and take pics as you go along.
Keep us up to date.
Best regards