If you can get several of the plugs out, or even if you can't, try a 3/4" socket on the crankshaft bolt at the very front of the engine with a heavy 1/2" drive ratchet or breaker bar. Pull the ratchet or bar clockwise, as if you were trying to tighten the crank bolt. You will have to do this from underneath the front of the car, but thankfully with Eagles, they are high enough that it's not a big deal.
If the engine turns, you're likely fine, and maybe your starter has given up the ghost as you've suggested. If it doesn't, I'd recommend pulling any remaining spark plugs and buying or borrowing a bore-scope to take a peek inside the cylinders, looking for damage.
But you may be jumping to conclusions. As stated by others, it seems highly unlikely that a perfectly running engine that just stalled from being idled too low during adjustments should have suddenly suffered any catastrophic damage without A LOT of warning signs. Similarly, it seems unlikely that your accessories (idler pulley, A/C comp, alternator, etc.) would have suddenly seized up without making a ton of obvious racket first.
Have you checked your positive starter cable connections, starter-to-solenoid, and solenoid-to-battery? If they are loose and not making good connection, you can turn the key all you want and the engine will not turn over.
Similarly, if your starter solenoid on the pass. inner fender has died, you're not going anywhere either. You can test this by BRIEFLY jumping across the big terminals on the solenoid and seeing if the starter motor turns the engine over. (Use a heavy jumper cable for this.)
Lastly, if your car has an automatic trans., one other thing to quickly check is at the very bottom of the starter solenoid -- the neutral safety switch connection. I think it's a light-blue wire. If the little push-on connector has come off the round terminal, the car will think it's in gear and the starter solenoid won't operate = engine won't turn over either.
There's all sorts of little minor odds and ends that can keep a car from starting or even turning over. I think you may have made the leap from "my horse has a scratch" to "my horse has a broken leg and needs to be put down" a little too quickly.
Please be methodical, and play with one variable at a time. For us to be of the most help, we need to know exactly what you've checked, how you've checked it, and results of each check.
Please keep us posted; we're here to help!
David