The quillbacks will most likely be a snack if stocked with larger LMB. It is possible they may spawn in pond conditions, but I wouldn't be sure on it. They are generally found in larger rivers and reservoirs. They spawn in back water areas, so it is possible they could spawn in ponds. They reach about 5-6" by the end of their first year and mature at 3-4 years of age. I would make sure you had plenty of mouths big enough to feed on them so not too many made it through their first year. If you get the SMB in by next year, they would be 2-3 years of age when the quillbacks first spawned if they do successfully. That would mean they'd be 8"-12" in size. Whether they could eat enough to control them, I am unsure...