Welcome to the forum. I have a smaller pond (about 1.5 acres) but with some similar fishery goals. I put a great deal of effort into reading everything I could find to increase my chances of success with YP, SMB and BT and I can share a little bit of that here.
Regarding BT, they are said to be the only trout (they're actually a char, but we'll stick with the term trout here to avoid confusion) to have a chance of breeding in a pond. There is an article in one of the archive editions of PB Magazine written by Mark Cornwell of SUNY Cobleskill where he details how to get the best chance of success with BT reproduction in a pond. If you call the PB office, you can buy that archive issue. It's well worth it.
I spoke to him about a year ago and he cautioned me that recruitment would be very unlikely with YP and SMB in the same 1.5 acres, as the BT fry would be snacks for the other fish. He suggested that BT do well in BT ponds, but don't compete well with other species. I would imagine that the larger the BOW, the greater chances of success with this. At 5.5 acres, you might have a large enough BOW to make your efforts worthwhile. If you're already building an area with hopes of getting WE reproduction, I would think that it wouldn't take too much more to make it suitable for BT reproduction as well.
Good luck on your build, and keep us posted on how it's going.
