Yes, it is possible. In fact that is my reply you quoted there. You can add separatate “.effects.darkest” files in “effetcs” folder, as well as “.buffs.json” files in “shared/buffs” folder. I have installed 4 custom classes and Trinket Overhaul Project, modified to use the new system. New classes were being added one at a time over 12 weeks of the campaign. No crashes so far and everything is working. Note that this works from the Radiant Update onwards, I use the 17462 build. I would post some screenshots, but attachments keep bugging out on me.
Hey are you the guy who originally posted about it on the steam forums? Different account name but you’re using the same portrait.