Is all your traffic going through the VPN? You can bind the VPN in the torrent client so that only torrent traffic goes through the VPN, while other traffic does not. This way, you should be able to connect to your local network.
Reading their other comments, i think they are not using a real number/a number they don't have access to, and signal is requiring to verify it/ "secure it" after the update. Thus, even tho the messages are stored locally they can't access it without doing something with the number
Using clips from other youtubers, historical footage etc would fall under fair use law (at least in usa, check your local laws) if you add your own content to it. There are detailed videos on fair use from youtube creator academy you can watch them.
3rd point depends on how the VPN advertises itself. If it advertises itself as nordVPN used to do then it's a scam. If it advertises itself what a vpn actually does then it's not a scam
Best way to explain is probably not explain at all in the beginning and let them create an account in a well federated instance. That will not make them confused and learn by using it.
In someone else's instance you can be defederated in two ways from an instance you want to interact - the instance you're in defederates - the other instance defederate the instance you're in
In your own instance you can see one option is gone now.
Is all your traffic going through the VPN? You can bind the VPN in the torrent client so that only torrent traffic goes through the VPN, while other traffic does not. This way, you should be able to connect to your local network.