tarkus666 has been testing the adaptor, and so far, it works fine with various Colecovisions from different regions, modded and non-modded AND including the accessories.
Only one minor issue left: There's some interference in the picture, which is worse the cheaper the USB adaptor is.
That shouldn't be a big thing though, probably only needs a different sized capacitor on the PCB.
I'll test the adaptor with an Oscilloscope to see what frequency needs to be filtered out from what power trace.
I've seen that on my Colecovision as well when I tested it - however, I thought that it might be my Coleco that's broken here (I bought it with a defective power adaptor and did an AV mod, so I thought the interference comes from that...)
But yay, it's working fine so far, so once that issue has been fixed, it's mass production time