Before I commit, is there a chance the trout are going to eat a lot of my small BG and LMB winter forage and stock? My pond is mainly for great BG. I don't want to disturb that significantly.
I don't think so. I think that they'd eat so few YOY bluegill that it might actually benefit your bluegill efforts. My experience with stocker RT says that in cold water they will love to eat some pellets, but their unfamiliarity with your pond would make it difficult for them to significantly impact your BG population.