Installed over two evenings:
At first i didn't know, that the Lynx needs a game cart to switch on and thus couldn't find the voltage on the mentioned points. Man was i sweating!
Then i prepared some floppy cable, but cut it too short so i had to rewire it...
Looks quite nice.
For now i skipped the VGA Port because i don't want to cut the Lynx case. Can somebody please point me to the information about "that guy" who installed a mini-connector into the brightness wheel cutout to fit some kind of adapter cable for the VGA out? Thanks @ McWill for the awesome Hardware.