It's been a decade since I kept seahorses. Loved keeping them, but after far too many losses, I decided these creatures were better left in the ocean. Hopefully, knowledge on how to maintain these animals has grown over the last decade.
As to Triton, I'm a brand new Triton system convert. The one worry I'd have is this: Triton Core 7 is dosed in equal parts based on Alkalinity testing... Seahorse systems are low demand, when compared to a typical reef, which is what the Triton system was designed around. I'd be afraid that the 3 (4) part core dosing system, in equal parts, would quickly overload the system on elements that a reef would consume, and that your seahorse system will not. Do your ICP testing, and be prepared to adjust the dosing volume of each of the 4 Core components independently, as needed.
As to biologic pathogens, even a 50% water change leaves 50% of any pathogens in the tank, and under the right conditions, bacteria will multiply far faster than water changes are going to remove them. I don't know that I'd worry so much about water changes, provided water quality stays high. I might discard the Triton method recommendation, and add a UV Sterilizer to this sort of system... that would seem a much more efficient method of limiting bacterial pathogens.
Very stable, cool temps are important with most horses... I'd consider a chiller a necessity. Triton core 7, independently dosed as needed, regular ICP testing, a nice, big, refugeum with enough light to out compete the reasonably low light you're probably going to have on the display, coupled with a UV sterilizer and a GAC reactor, sounds like a very good plan for a seahorse system to me.