The space available is, I said, very small and so all the receivers are in a "stack" held together with cable ties - otherwise I found it impossible to keep everything straight and tidy - it's would be a messy job to take it all apart and then put it back together after flashing the Solo2 and installing the plug-ins!
Anyway, the other 4 receivers are all closed-source and so, for those. it's simply a matter of plugging a dongle in to see if it is recognized or not (most basic ones appear to work 1st time, but some never seem to because the relevant drives are not installed in the closed-source firmware, and I/we can do little or nothing about that) and then, when I find which one(s) works in a box, using the Setup routine to get it connected the Wifi.