Welcome to Pond Boss.
All first three types of fish you mention like brush piles/X-mas trees as structure, but that structure degrades over the years and needs replaced as time goes on; there are other types of man-made material structures that you can use too.
Yellow Perch and Black Crappies are predators, so maybe HSB may not be needed, or at least may take some 'food' away from the crappie and YP.
You may want to get fathead minnows stocked as soon as you have even a foot or two of water in there, but if that shallow over the winter, you could freeze solid which would kill most of the fatheads if not all of them.
Some swimmers say that bluegill actually bite them when swimming. I've never experienced that, but others swear by it, so keep that in mind.
