I've added a ODROID C0 embedded into a CM15 here which I've posted about elsewhere on the forum here so I won't go into the build process of it here.
Also updated my OP to reflect its addition.
Currently this is only used to test another Linux HA software Domoticz this is running along with my Pi + HomeGenie setup so I have no macros or timers currently configured it it which might conflict.
I'm watching others posts on using Domoticz and their setup progress. I'm not conviced Domoticz is going to perform for me as yet
there are some asspects I like about it and it is frequently updated unfortuneately the documentation doesn't seem to get updated as frequently.
At least thats what others postings suggest.
To fully test the ODROID I'll need a USB hub even though this has two full sized USB ports as my though is this will eventualy replace the Pi 3B+.
I've found a small unpowered hub which also includes a Ethernet connection which will provide faster streaming abilities then currently possible with it.
The issue will be if it will work being none powered
The use of an external Wi-Fi will allow for a more powerful wi-fi board then the PI and an external antenna though I've not had an issue with the PIs wi-fi.