Even if you are already working on the problem, here are my findings:
Wifi is already working, but the default-gateway and DNS is not set at all.
If you manually add default-route and DNS-Servers then internet connection is fine on todays build....
I´m using this one. Works fine and the air-stream keeps the phone cool.
Maybe this Desire 620G-thread is a good start for you.
The idea with the modified recovery was, to do the first repartitioning with the temporary modified filesystem and after that boot the new layout with an kernel modified the same.
Unlikely the boot- and recovery-partition is not changable from run...