Welcome to Pond Boss.
Your pond is beautiful.
No matter what specific plan you embark on, removal of a vast majority of the bullheads, I think, would be a major component.
For me, I wouldn't want to invest in my desired fish species until I had the bullheads in more control.
Welcome to PB cafl !
I agree with what Sunil posted above. There are options but most people don't want lots of Bullheads for a variety of reasons. For newer pond owners it is worth mentioning that the more complicated the plan (# of fish species) used the harder it is to keep things somewhat balanced.