If the other members want to talk to you then it is okay. Keep in mind not everyone wants to

Yes u can, this site is not restrictive

You can be on more then one team. I don't think there is any restriction on conting someone outside of this website. As long as both people agree.

You can be on more than one team, and have pen pals as far as I know or even email each other if you don't want to use snail mail.

Here’s the official answer:
To contact another member privately, you can post your email address or phone number directly onto their page and it will be visible to only you and that person. You may then communicate offline, privately.
How about that? Cool 😎 huh? It’s freakin Awesome I tell ya! YAY!
Hugs 🤗