Well, after doing a bit of re-installing (both Vortex and B&S) it doesn't look like I get those errors anymore.
Now, I'm not sure if this is a game or mod bug, but some of the weapons that I downloaded are just question marks "?" and I can't spawn them.
I have B&S 8.4 and the mods are also 8.4.
There should be a notice about this on the Vortex dashboard under "Announcements". There's a problem with 8.4 where mods installed in Vortex don't work. We've been speaking to KospY (the developer of the game) and this will be fixed before 8.4 leaves beta.
You'll want to use v8.3 for now if you're using Vortex for your mod installation.