Based on your visual assessment of "There are still some decent size bass in the 1lb range in the pond. I don't have any sense for how many but I have caught a handful. I can also see quite a few packs of LMB in the 6" size range lurking off the end of the dock. There still seems to be a healthy population of bluegill but they are generally pretty small."
If you are correct about a "healthy population of BG", then I don't think and I am confident you do NOT need to buy more LMB. Your 2 acre pond will grow bigger bass more quickly when fewer bass are in the pond rather than lots of 8"-13" bass.
As Theo suggests: I would buy a 20ft to 50ft minnow seine. (A good place is Douglas Net Company. Tell Kelly that Bill Cody referred you).. Use the seine to sample your fish composition in the beach area. Do it every year. You can use PVC pipe as seine poles . You should be able to find a few small young of year LMB in the net seine samples. A few sampled 2"-4" LMB plus your several observed 1lb LMB and a few packs of 5"-7" LMB will be MORE than enough bass to get your 2ac pond quickly by next year back to LMB with sizes of 2lb as noted IF the bass are well fed producing growth ratea noted above by esshup. LMB will in OH will grow 1 lb per year IF they are not over crowded (to many per ac) WHEN they have enough of the RIGHT sizes of BG to eat (esshup above) .
LMB stop growing around 1 lb per year when they do not have enough forage fish to eat. If the pond in 3 yrs doesn't t have 4lb to 5 lb LMB then there are likely too many bass with too few BG of the 3"-5" size group as easy catch food. For growing 3lb - 5 lb bass ponds usually have too many 9"-12" LMB AND not enough BG / sunfish & forage items.
Don't buy any more FHM for stocking if you want to grow bigger bass. Lots of reproducing BG will easily grow 3lb to 6lb LM bass WHEN the bass are not over crowded. Each adult bass can and needs to eat 300-400 BG per year. to grow that 1 lb per year. When the bigger bass are not growing 1" as an additional 1 lb per year they are not getting enough of the adequate food.
II think the reason your pond prior to the fish kill did not have 4lb to 5 lb bass was there were too many bass. The fish kill may actually have been a plus for the pond not a big negative,,,, IF your goal was to have some larger bass in the 3lb - 5 lb sizes.
Over the winter read, reread, and learn a lot about what it takes for growing good sizes of LMbass in this long thread:
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=255372#Post255372
