Porkchop - get the FHM's as soon as you can and put some breeding structure in for them like pallet stacks...
One cinder block is NOT enough for a two stack, don't ask how I learned that lesson and I'd use at least a block per pallet in the stack. My pallet stacks ended up being about one foot below the surface and some of the bottommost pallets in 3 to 4 foot of water. I put about 1000 FHM's in my 1/4 acre pond in April (2017) and by the end of the year I had so many that I was worried about bio mass capacity (unneeded concern obviously), but their ended up being massive amountsof those buggars for my stocked fish to forage upon. If you wait until you stock the fish, you will be mostly feeding the new minnows to the fish, given that your stockers will be big enough. Even at that, the fist spawn of minnows will be decimated rather quickly.
I would look into crawdads and PK shrimp (I think their is a northern version) if you can source them. Walking the creeks last year catching crawdads took me back to my youth...rubber boots, a bucket, and a net, it was like I was 10 again.