I can give you an alternative to having an ILDA multi pathway to lasers without ANY need for soldering etc... I use QS and know of and use multiple laser systems on one dongle. You did use the word "mirroring". Well its been sometime since I did that but I have done it and It didnt cost the earth in fact nothing at all.
All this "ILDA" stuff right, when it comes to the wiring was not invented by Pangolin or anyone in the lw its just plain old computer cabling. Thats your first clue. Think about that for a few moments and a light bulb should go on.
Mirroring is "simples" but only if your laser units have "IN and OUT" ILDA ports.
I cant say for certain that daisy chaining always gives mirroring since the wiring may be "whatever" depending on the manufacturer.
You will have to get "Y" splitters DB sub 25pin. And experiment.....!!!!
Hope this helps mate.