Overstocking of fish that will not reproduce is ok so long as you make room for them. You can slide in some HSB and WE pretty easily if you remove a few LMB. 8"+ HSB and 10"+ WE should have some fairly good survivability even if there are 18"+ LMB. Stock late in the season when you have a better chance of receiving larger fish from the supplier.

1/8 acre pond should be fairly easy to remove some LMB to make room for other predators

Mat Peirce
1.25 acre southeast Iowa pond
LMB, BG, YP, WE, HSB, RES, BCP