just for a correction, no one know what the original flowerhorn was made up of, and was certainly not just a midas and a trimac, al they know was it was made up from anywhere from 6-8 CA cichlids, not just 2
if you sign up on the flowerhorn forum they will tell you it is NOT just a midas and trimac.
75 is the bare minimum foot print for a flowerhorn, as with all large cichlids, you should double the filtration.
as for the Bp tankmates, you probably wont get away with just one, you will need several, or the flowerhorn will just kill the Bp.
you pair them, assuming you have a Zz (Zhen Zuo, the most common strain of flowerhorn) you can breed it with a Bp and you will get some neat fry, Kamfa and Bonsai, both are very neat looking.
if you have questions about your flowerhorn and want some really god answers, sign up on flowerhorns.org , they have some of the most knowledgeable people their when it comes to flowerhorns, and they are very good people and do their best to help out, i suggest you ask them for info
im not trying to say you guys dont know your stuff, but people on flowerhorns.org will probably know better.