Mosfets gate driver IC criteria
Take the gate charge and multiply it by the frequency. This is Coulombs per second, aka Amps. As long as you're fully filling the gate capacitor every cycle, this is correct.
I believe Ipk is (Vgon-Vgoff)/Rg, which is the charge flowing into the gate capacitor right when you flip it on.
Keep reading those app notes! There's lots of info packed in there.