Ten years ago, I've installed a Unicable system in our house, working fine with up to 4 TV sets, or satellite receivers.
We already had single shield coax cables here, for cable TV, therefore Unicable allows to reuse this, w/o replacing it by double shielded, four fold cables, which is necessary for the 'normal' satellite systems. You probably need to replace each terminal box with ones which have integrated protection diodes for the Unicable system, and which have appropriate damping factors, depending on, at which distance from the star / entry point they are sitting, that's a bit of trial and error w/o appropriate measurement equipment.
I have chosen a cheap Sharp LNB, BS1K1EL, which works well with different receivers, and also a relatively new Samsung TV set.
This LNB has one direct Unicable (they call it SCR = Single Cable Receiver) and one additional legacy output, where you can attach a fifth receiver, using a separate cable.
So you don't need any additional converters, PSUs, and so on, that's the most simple solution.
I also tried an inverto LNB, 'Black Unicable', but that did not work at all, obviously it was intended for inverto receivers only.
The setup of the different channels is a bit tricky, and your receivers / TV sets of course must be capable to manage Unicable signals.
Frank