Ok there's more progress: I took the zzz-tv-cvbs.patch and copied 3 hunks: the new file sun8i-h3-tve.dts, the orangepizero dts patch, and the orangepi-pc.dts patch, into a new additional patch.
Then the compilation finished 100%.
I was able to connect with ssh, run armbian-config, system, hardware. And I saw the tve dtb overlay option
I selected it, rebooted, and after a while I saw the login prompt in my composite TV (with overscan and ghosting problem)
I tried "apt install lxde". Reboot. But I only had the text console
"startlxde"
Gtk-WARNING **: {time}: cannot open display:
Maybe I am very close... but maybe I am very far.
update: "apt install task-lxde-desktop", reboot... and I was welcomed by the lxde login screen
BUT it was the same "smeared down from the mouse cursor" experience as I had before trying the LibreElec patch.
Perhaps the zzzz-tv-cvbs.patch's DTS is different from the libreelec dts... since it was the only part that wasn't sourced from the libreelec patch.