First of all, the addition of tilapia improving bluegill condition doesn't intuitively make a lot of sense to me, but it's likely because of my very poor understanding of what it is exactly that tilapia do. I'm really uneducated about them.
Your reasoniong seems sound, in particular #2, but my opinion on this matter probably doesn't hold much weight. Sounds like a good Overton/Grimes/ML/Lusk type question.
Holding a redear sunfish is like running with scissors.
