[Q] Stock D802 20h CM12 flash advice topic

Hello all,

I have a stock 4.4.2 20h d802 that I plan to reinstall with cm12 as soon as m1 is released.
I've read a kazillion threads here and thought I had everything covered but the more I read more variations I can see.

I would prefer a PC free solution.

20h blocks towelroot so I guess I have to use stump root instead.

I have the following plan. Any advice or anything missing in here? I do not want to brick my g2 :)

1) root with stumproot 1.2 apk
2) install autorec apk to automatically downgrade boot loader and install old twrp
3) upgrade twrp to 2.8.3 with zip file from recovery
4) erase cache from recovery
5) flash cm12 from recovery

But now I am reading stuff about baseband flashes and that lollipop needs jellybean stuff. So am I missing something our am I good to go?

When I flash lg official rom I have to choose the specific 32gb version. Will this be okay with generic cm12?

Thanks for any help!
Stefan