I think it doesn't matter what LOR supports if your using xlights. There are risks, because LOR could change the file format and/or xlights might not add support for pixelnet networks, etc.
I can't speak on how the xlights team will be implementing it ... but basically xlights reads a LOR or Vixen sequence ... and then plays it for you, outputting to the Network(s) you have mapped out. So you can have multiple Networks if you want. [ i.e. LOR + DMX-Entec Pro/Lynx, or LOR + Pixelnet Lynx ]
It replaces the LOR scheduler and show editor ... as you would use xlights as the scheduler and show player ... in the the LOR scheduler. You would loose show on demand capabilities.
You instead build xlight playlists (like LOR show builder) and assign them to a calendar (like LOR scheduler) ... but its all built into the xlights "scheduler" tab currently.
You would include all the sequences into an xlights playlist (or lists if you vary your show) ... and then assign the playlists to times and dates on the calendar. Then xlights runs your show for you.
When you map out your xlights channels ... you just map out the "Network(s)" you are using and it'll play them that way.
So say you had 32 channels of LOR, then added another 512 channels for DMX (via. pixelnet, from hub say) ... and then added another 60 RGB channels to control 20 SS modules via. a Pixelnet flashed Lynx Dongle -> SS Hub -> SSC.
So hooked up to your show computer would be the LOR USB interface (on one COM port) and the Lynx Pixelnet Dongle USB interface on another COM port.
[ ok, yes you have up to 4096 per pixelnet universe, but lets just say your using just 512+60=572 channels total, for this example ... say 1=512 are for DMX via. the SS Hub out, and 513->572 are for the SS modules on SSC#1 ]
Then you would map out a LOR network for the first 32 channels in xlights. Then map out the next 572 channels to a Pixelnet network for the rest of the channels .... in xlights.
My guess is xlights might add Pixelnet and E1.31 as new "network types" ... where currently it supports only DMX-Entec Pro/Lynx, LOR, D-Light or Renard as valid network types.
So in reality, you would set it all up as a bunch of LOR channels, so I think in say LOR S3 it might be 2 LOR 16ch controllers (first 32 channels) and then say (600/3) 200 RGB channels after that. xlights doesn't care what the hardware is, but you tell it whats what.
ch 1-32 LOR Network, ending channel: 32
ch 33-633 Pixelnet Network, ending channel: 604
So really the first 32 channels in your LOR sequence would be output to the LOR network, and the next 572 channels would be output to the Pixelnet network.
Again, not sure how they'll do it ... but hopefully this shows how it might be done.
So from a sequencing standpoint ... your just sequencing in LOR (or Vixen) ... whatever you want.
The other option is to go with LSP with supports this already, but is awaiting version 2.x still.