Guys, soldering is not a problem - as suicidal_orange mentioned, USB-C has 24 wires, I don't have any electronic testers/equipment or knowledge to test and find out.
I can solder simple 5 wires as I know which ones are in JST plug.
ALso, don't worry about breakout board position - I will mod keyboard casing to accomodate it - I picked a place as well - it will be 2-3cm from the center cable channel. I will take apart my R2 and measure all things later on, but I can screw breakout board down to bottom piece of case, dremel out some plastic, then wire it up to pcb. I would drill a nice, long rounded hole out on the back of the top case, so it would look nice.
Only thing is to find out all electronic issues.
All USB-C breakout boards I find have 4 pin out socket for 4pin JST plub. How to connect them with R2's 5 pin?