Is this the place to begin the process for renewing a Class C license with Hazmat Endorsement? If not can you please steer me in the right direction?

Yes iwx has the TSA background check system.

DMV said to start at Neergard to take the Hazmat test. But it looks like it's a trucking company. Confusing

Yes they do the fingerprinting for hazmat

I'd start with the DMV