Just follow the basic social media rules and you'll be fine. Also don't trust anything that is clickable unless you hover over the link/copy it to some text editor.
Those are not PII tho. What you're sending is just how much RAM you have, system and OS information and that's pretty much it. I'm sure Gaben won't send an assassin on you based on your HW specs.
Should you store them in the password manager itself?
No. Yubikeys support storing 2FA keys on hardware. Just buy one, they start from 33€. AFAIK even hardware wallets support storing sensible stuff on them right next to crypto.
I meant that you need a phone number for registration.