[Thaeris]

And it's also on sale until 16 January, unless I'm mistaken:

https://www.gog.com/game/tachyon_the_fringe?utm_medium=email&utm_source=newsletter&utm_campaign=20170113_weekly_sale&utm_term=EN

Tach has to be one of the best feeling space sims I've flown. It does not feel nearly as "mechanical" as I recall FS being - the game plays fantastically with a joystick, even a well-worn Logitech 3D Pro. The narrative is also very enjoyable - pair that with the aforementioned sense of motion, and you've got a good time in the works.

As per Zinv's mod working properly with the GOG version, I cannot say. But I'm quite certain that the man will at some point!

[JGZinv]

Multiplayer unless it's over a 3rd party service as virtual lan still doesn't work. But so long as the game files are accessible the other mods will.
All my launchers were based off a targeted directory, not the install directory or registry entry, so you just need to know where it's installed.