Bubba, You can start stocking after you do a water quality test on PH and alkilinity. Alkilinity comes from your soil and takes a little while to affect your water. It should be ready to test now.
You can put the crappie in. Heck, its your pond. Just understand the penalties of having to start over in a couple of years and having a minimal bluegill forage base. I love crappie too but wouldn't stock them.
Dealing with the local DNR is a personal and financial choice. I would talk to them and find out about their stocking "recipe" and whether there was any wiggle room on the catfish. Check into prices and availability of stocker fish now and make your decision.
I'll leave aeration to others.
