I’ve dated people who don’t eat meat. I feel like by and large they understand what a BBQ is. As others have mentioned I always do some sort of salad or vegetable based dish just because it’s good to have some greenery in general. Failing that surely there’s decent vegan mayo by now. You show me someone that says they don’t like potato “salad” and I’ll show you a damn liar.
I’ve had plenty of vego/vegan mates be cool at these sort of events. Yet to see the hoard of gate crashing vegans turn up to a BBQ demanding specially catered food that they could probably guess won’t be present.
Why not back up your win 7 installation and try a different Linux variant? Or even just fuck around with Linux in dual boot/vm before transitioning? I’d have to imagine that’d be preferable to either not using the internet or risking every device on the same network it’s connected to. I swear I read an article where fresh win10 installs were getting infected within minutes of connecting to the net. Let alone 7.