[werk_ag]

I put myself the question length of the cables.
For SHTxx, I believe that one can have +/- 1m wire without problem.
For the PMS7003/MH-Z19, I did not find information. With is your opinion 1 m of wire good?

The cables for the PMS7003 and MH-Z19 should be very short, no more than 15cm.
In the case of the PMS7003, don't extend the cable that comes with the adapter, just cut it at one end and put a suitable set of male female connectors. Pin headers like the ones in your picture are perfect.

Regarding the SHT31, yes, the cable can be longer (with a twisted par cable), but its preferable to have it near the other sensors.