This thread points out one of the interesting and frustrating points of stocking (LMB or BG or Other) into a pond with existing predator fish (BG can be a predator on small LMB). The issues is guessing at the survival rate. It is highly variable. Problem arises if you are stocking anticipated top end predators and miss badly on the survival rate (anticipate 20%) and you get high survival (say 75%). My guess was 25-30 % survival in this situation. If my guess is way off and you get 70% survival that would normally be a big issue. Except in your case you stocked very low to start , which is a good idea IMO. Plus it sounds like you may have more water (size) to come for the fish to grow into. Feeding and the size of the BG could easily result in 75% survival of the LMB. This will still be low for your situation but very good IMO. It is much easier to stock low on LMB and add later as opposed to stocking high and having to remove lots of small LMB. I would bet that all turns out well. The way to check is watch the size of LMB patrolling the shallows and next spring look closely for LMB spawning and yoy survival. Keep us posted on what you see.