Marble floors are harder than iPad glass.
See my post here:
Excessive heat can damage the LCD under the panel, restrict the heat gun to the outer edge.
Use more than 6 guitar picks. 12 would be a better number.
The ifixit manual stops when you get the old one off. It's up to you to figure out how to put the home button, camera bracket, and new adhesive strips on the new setup.
If your glass is broken, it will break more. Safety glasses!
If your glass is broken, expect about 3 hours repair time. It sucks getting all those little shards off.
If your glass isn't broken, why on earth are you replacing the panel?