My question

is possible to get 2 msgr apps on the pc? without uninstalling the first app?
same goes to msgplus

Like run 2 editions?
If so, you can either use MSN Polygamy on a copy of 8.1 and fetch a portable copy of anything older than 8.x (Somebody really early in some thread said it might not work, but patching 8.5 and 7.5’s exes with MSN Polygamy did the trick for me, all I really did was did some messing with the exes, by temporary replacing the 8.x exe with the other exe, moving it back to the portable folder, and patching 8.x) or fetch the files from a VM after install, or 8.x+ (msg plus live) supports a simular feature.
I highly suggest NOT doing this due to how insecure it is, but I’ve tried, and I managed to install 1-3 after installing 8.1 alone, it doesn’t seem to give an error about being outdated.
It actually does work too, but I forgot where it extracts.

welp… for me that’s hard