DevDoc

I found the wireless kit posted in the UK. It appears ligit as I searched the part number and found several results. The pictures look correct as well. https://www.overclockers.co.uk/htc-vive-wireless-adapter-clip-for-cosmos-vr-headsets-99h12185-00-vr-014-hc.html

I saw the adapter kit on a UK website and it looks like just a smaller pad, the clip to go around the head strap that you already have, and the cable which I believe is the exact same as the vive pro one. I think if desired you could just trim up or cut the pad to fit for the cosmos. The software recognizing the Cosmos will be the trick, however being that the unit is on sale already, and I just received a software update for the wireless software, perhaps we are in luck. Crossed fingers. See the link below with part number. If you search the part number, you will see several vendors who have the same listing in Europe. https://www.overclockers.co.uk/htc-vive-wireless-adapter-clip-for-cosmos-vr-headsets-99h12185-00-vr-014-hc.html

I am using this one. I believe any USB 3.0 Cable, Type A to Type A should do the trick. I bought mine a little longer to put the battery in a pocket. https://www.amazon.com/gp/product/B01KRO8D20/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Not sure you are asking the correct question, but I am using the Vive Pro with 2.0 Base stations (link box attached to control lighthouse power management, not needed) and the wireless adapter with the pro kit for connecting it. I believe your setup is considered standard.