Thought I would post this here, taken from the Kickstarter comments:

Originally Posted by Larian
We definitely haven't forgotten about it and are busy with it. The problem here was that we needed to align three constellations but that's almost done. Everybody who didn't use their Steam key can already get their GOG version, and everybody who used their Steam key can already play via Steam. The only problem left on this front is the transition. But the save games that you make with your Steam version are compatible with the GOG version, so once we're done (which I hope is today), you'll be able to make transition smoothly. We prioritised the people who didn't use their Steam key as we figured that if people were already playing on Steam, it wouldn't be that much of a problem to wait a few more days.

This is good to hear. I know some of us were afraid that if we started playing the official Steam release by using the code provided on the Larian vault, we might get completely locked in and be unable to redeem our GOG key later. This gives us the green light to continue playing on Steam as we did in the alpha/beta and still change it to GOG when available.

DOS2 Mods: Happily Emmie After and The Noisy Crypt

Steam Workshop
Nexus Mods