Hi Russell,
The XU4 odroid works well for me. It needs cooling as it produces more heat than a Pi. You can get built in fans and heat sinks. WiFi is just a plug in arial so factor that in. I have put mine in box with fan, motor focuser, dew controller, 12 volt distribution supply, and USB3 7 port hub and. A single 10 A 12 volt supply supplies the lot with a step down for the Odroid.
There is a new Odroid, the N2 but VNC possibilities are limited (No Machine is the only one that I know of that works). Team Viewer works with the Odroid (not Real VNC). I run Ubuntu Mate and is generally pretty stable (well as stable as KStars gets anyway
.
Happy to advise if you take the plunge.
Mike