Now that I have moved, My cable now comes across an rj45 instead of coax on that second line coming out of the modem. Somehow I need to figure out how to get the new channels into Kodi.
Something's missing here.
What you describe is NOT standard television. It doesn't sound like there's any standard frequencies or types of signal coming out of there. The entire third party tuner world expects coax wiring, and either ATSC or QAM signals over that coax wire, on well established cable frequencies.
At the very least, you're missing the coax wiring. And if it's true IPTV, you're also missing the standard QAM signals over standard frequencies.
What you describe sounds to me like a completely proprietary system that requires the cable company's converter boxes to work.
So tell us: if you asked the cable company to come in and give you whole house DVR, what would they install and how would they install it?