Re-assembly tip: when I took the screws out, they showed residu of Loctite. Remember to put a tiny bit of Loctite on them before re-assembly.

Indeed, heat and apply time matter. I took the shattered glass off from my LTE iPad Air 2 more easily than on the donor wifi iPad Air 2, I couldn't seem to separate it on the donor device. I decided to increase heating and apply time: heated the iOpener 1 minute, and applied the heat for 5 minutes (doubled everything) and yes, it now moved just enough and I could get the picks in!

Difficult when glass is shattered. Any tips for that?

As indicated, carefully remove the metal plate where the antenna is soldered. The plate is glued to the unibody topcase. It came loose when forcing a long strong tool like a flathead screwdriver underneath (spudger too weak) and following the metal plate from the hinge down along the superdrive opening. Careful not to damage the solders. The metal plate is so thin it could tear, but it comes loose quite evenly. Careful here!