If you add in the $200 or so for the cost of the FX5 and the $50 or so for the other filter/aerater supplies, you are pretty deep into the cost of the feeders.
I think the week of the delivery you are going to have substantial feeder losses (not that it really matters). Going from 100 feeders to 1000 feeders overnite will be a ton of strain on the bacteria to keep up. Feeders will die and foul the water leading to more deaths in a cascade effect. My LFS keeps feeders in a 120 gallon tank with 2 emperor 400s and a bubble bar with daily water changes, and they have 5-10% fish loss every time they get a new order in. They throw away the dead, but you could presumably freeze and feed the dead.
If you were going to maintain a stable population of 1000 one inch feeders in your tank, you would likely be successful (lots of water changes to reduce nitrates). It's the swing from low to high biodensity that causes the problems.