I confirm I have managed to launch the game with the above guide on Ubuntu 18.04.
The crucial part was installing wine to the 5.0 version (currently I'm using 5.0.2). Ubuntu 18.04 has wine in the repo only in 3.6.0 version and with this one I couldn't connect to the skylords reborn server in the login in-game screen. The guide to install wine 5.0 can be found here: https://tecadmin.net/install-wine-on-ubuntu/
Although I have one more issue. Before every launch I have to remove configuration file from "~/.wine32/drive_c/users/<username>/My Documents/BattleForge/config.json" otherwise the game is crashing. Thanks to Deck on discord he narrowed the problem with the config.json, so it could be edited to the form below having the most important one (although I didn't test it because it was more convenient for me to just delete the file):
Happy gaming on Linux!
I have narrowed the problem with crashing because of config.json. All you have to do is to remove the below line from this file and the game crashing will be gone. That's all!
quick update on the lutris installer: it should now work correctly (before there was an error in the script syntax that apparently the mods and me oversaw which made the script do nothing. I am testing it right now but it does what i expect it to be doing (asking for the archives and now installing dotnet).
So if you are still having problems (or tried the installer before) give it another go