Antenna wire spec and routing

With regard to the universal RF module:

I am currently preparing the universal module assembly based on V1.3 PCB still awaiting delivery of some missing parts.
Some of my RF modules are carrying a PA plug while others got a soldered antenna wire.

Indeed I would prefer to solder individual RF antenna wires to all modules avoiding the connector solution.

Does anybody have collected experience for:
1) antenna wire specification (I guess coax, probably 50 Ohm?)
2) antenna wire length (overall, and the final core wire length)
3) antenna wire routing in the TX housing case of using all 4 modules

Once more thanks a lot to all of you for your help!

Any coax 50 Ohm will do. I used something like RG-174 or RG-178. The overall length is not important, the longer the cable and the thinner it is the more loss it becomes, but at the distances we're talking about it's all very minimal. The attenuation is 0.2-0.4 dB/ft, so your 10cm piece will attenuate signal by 0.1dB.

The final piece with only central wire should be matched to 2.4GHz. It should be quarter wavelength, that is 31mm in length. Matched BODA antenna is better, but it takes more space and there is no chance to push it through antenna case already installed.

It is theoretically wrong to put two antennas very close to each other by their active parts, it can attenuate signal a lot.