Everything is fixable with console commands-

First, try force dismissing broken companions, you'll need to get their refid first though (so maybe load an older save, or just search for the refid with the help command - ie. help mountbatten 4 npc to search for 'mountbatten' in refids that are classed as 'npc')

For reference, since I have it written on a post-it in front of me, Mountbatten is 082c1edc (08 may be different if londonworldspace.esm is in a different slot)

To force-dismiss Mountbatten-

prid 082c1edc
setconsolescopequest followers
emptyrefalias companion
setplayerteammate 0

To move Mountbatten to you-

082c1edc.moveto player

Try to get Mountbatten to join again normally, if he doesn't, to force-enlist a companion-

prid 082c1edc
setconsolescopequest followers
forcerefintoalias companion
setplayerteammate 1

Now I'm honestly kind of glad that I've been too lazy/depressed to figure out how to get FOLON to run on Linux. I really hope they fix all this...

Probably a spaghetti code mod on top of an already terrible game engine. It was bound to become buggy. Even Bethesda themselves can't be arsed to fix their engine and games.

I gave up on it for now when the questline involving the NPC learning to write broke, and then I started crashing to desktop (without any logs anywhere, either in the Buffout directory or even in Windows' Event Viewer) every time I left the Swan or fast traveled directly to it, even though traveling to another point literally fifty feet south worked just fine. And since there's no logs describing the crash, I have no idea how to fix it.

I could probably fix it by uninstalling and re-downloading it again, but I have a goddamn data cap that my roommate already blows through every month with the fucking massive updates Fallout 76 has taken to pushing out, I have zero desire to download 60 GB of data (30 GB base game + 30 GB FOLON) every fucking time I sneeze wrong and make the game start crashing again. =|

creation engine quests are too easy to break as the game gives you lots of freedom to mess with progression and characters, eventually someone finds another edge case

if you dont test the fuck out of them they will bug out in some way

Do I have to play fallout 4 first before I start this?