Any chances they appear on GoG in near future?

I would doubt it since crossworlds hasn't even came out yet. Which is just an expansion of Armored Princess so it shows the developer aren't yet finished with it (though they released the rather nice editor with crossworlds so I would say they are now finished).
On a side note, Crossworlds is good! I've been playing it for the last day and a half (steam accidentally allowed downloading, they have now blocked that but I have it on my offline machine so I can still play it) and really enjoyed my time with it. The two new campaigns are annoyingly short but it has given me a reason to play through the main campaign again, which I am enjoying the new content in.
The editor is very intuitive as well, haven't had much time to use it but I managed to create a nice little island in an hour or so.

Here's hoping, but I imagine it will be two or or three years.

You can get them on Impulse, however, another small game seller with excellent service who also dislike DRM. The Impulse versions do have DRM, but only the very non intrusive GOO.