I have had several accounts banned on this laptop I'm using now, and the IP is blacklisted.
Is it enough to have a new IP address by using a completely different internet connection? (I bought a new usb internet)
Or does facebook also track the actual machines IP due to footprints, meaning I need to use a different computer or buy a private VPN?
Thanks
different computer or use virtual machines. fb does track ip addresses.
When Facebook bans you, do they ban your personal account too or just the ability to post ads? I used to run ads on my personal Facebook account back in the day but then switched to a separate account focused on just advertising. I'm wondering if that advertising account ever gets banned if they'll ban my personal account as well.
Your personal account will be fine, they will just limit access to the ads manager.
There is no such thing as a computer's IP address. Whatever computer/device you put on that connection will have that IP. Use a VM or a specific FF profile just for the second FB account using your USB 3G/4G modem.
Anyone know if the ips be in the same c-class?
i don't think it matters as long as they are different
i don't think block ip makes sense. what if you are a student and on a campus behind a proxy server. In the eyes of internet, it's just 1 IP even a lot of students doing facebook ads
so it's not wrong right 
No one really knows for sure. Better safe than sorry. Besides that tho, I'm sure FB has some restrictions removed for cases like this.
my account got locked after logging in from a school network^ indeed just play it safe in all ways possible
ironic that they would block school networks...