Welcome, Jeff.
You could keep some of your bigger BG for restocking, and building a forage base faster. If wanting trophy size LMB, I'd start fresh on them, because you never know if an 8" LMB is a yearling, or older and stunted. A stunted fish can grow, but size gains lost can never get made up. Save some RES if you had some also!
Have you considered using a siphon system to drain? I can't imagine a 3" electric sump pump draining 6 acres in 40 days...40 weeks, maybe. Electric pumps have a low head pressure and flow rates drop REALLY fast with each foot of lift. A temporary 6" siphon would drain it fairly quickly and can be installed permanently if wanted later.
Give me a call when you start draining...I may be able to find new homes for some of the panfish....not the crappy ones though!
Edit: Be sure to nuke any remaining water heavily with HYDRATED Lime to ensure nothing survives in the puddles, or your draining will be a lot of wasted time, money, effort, and fish restocking.
