Hey guys, I have a few questions about CentOS.
I try to do my best but your questions aren't very specific
Is it basically the Debian of the RPM world?
Depends on what you mean by that but yes the comparison is kind of legit, both focus on stability over bleeding edge software and features.
Does it use the same repositories as Fedora?
No it doesn't.
But there is the Extra Packages for Enterprise Linux (EPEL) community repo which can be used by Fedora and CentOS.
If I'm familiar to the before times of Fedora 22 (back when Fedora used YUM), I'll be right at home here, right?
Well depends on what you mean by that
If you're used to yum, that's the package manager of CentOS at the moment, yes.
It works the same way as it does/did on Fedora.
To clarify the relationship between Fedora, CentOS and RHEL:
RHEL is based on Fedora, CentOS is basically a unbranded spin-of of RHEL.