Minix Neo Z64 can come with Android (that’s the one that I have) or Windows.
Streams are a bit easier to setup on Android device to be honest, but in this case you’d need new device(s)
As for Windows client, is it capable of displaying 4 videos at once? Definitely yes, although again it might depend on PC spec and the video quality etc.
Also as I’ve mentioned, live streams on Xibo for Windows are a bit more tricky to setup
Please have a look at this guide: