I might miss a device in this list, feel free to add/clarify. I’d like to know how many of each can be connected to a single mixrack and control it simultaneously.
dLive console
IP6/IP8
dLive MixPad
dLive OneMix
dLive Director
ME-1 (does this actually control the mixrack or is it merely fed audio signals from it?)
IP6/IP8 connections are limited by the dLive software to 16 each (on MixRack) and 16 each (on Surface)
ME-1 is a standalone personal mixer. It receives audio from the mixer. You can daisy-chain as many as you like, or cascade switches / ME-U hubs, there is no limit.
Firmware V1.4 (out at NAMM) gives the option of an independent view on the VGA output, so you can have a third screen on top of the two touchscreens.
MixPad and OneMix always connect to the MixRack. Director and the IP Remotes can connect to either (this is regardless of where they are physically plugged in, since all devices live on the same network). When connected to the MixRack, they act like independent controllers, whereas to the Surface, they share some elements of the Surface e.g. the strip layout for Director, or the Mix/Sel keys for IP6/IP8. Have a look at the Director Help and IP6/IP8 User Guides for details.
Like everyone else, I think an important update will be the ability to have at least 2 surfaces, or even more (eg FOH/MON/RECORD/BROADCAST) able to connect and control a single mixrack.