Yes, lead is fine
No , no stamp needed
Yes, e-callers are ok to use.
I use whatever I have. Target lead loads, leftover upland loads, last year's steel. As long as I know what it is to adjust my lead, etc.
You can hunt 1/2 hour after sunset, unlike waterfowl.
I believe you can unplug your gun as well.
I prefer to use a mouth call... seem to have a lot more luck with it compared to my e-caller. Actually, I didn't bring the e-caller out once last year. Its nice because if there any around and you call correctly... they will be there in less than 1 min. If I don't have time to decoy and sit I will drive to different spots and call for 5 min. If nothing, i will move.
There are some on here that make my 10-25 crows a year look like a few hours worth of work, so I am far from an expert. But it sure is fun.