I'm CCM, as well, and was in contact with practices before fellowship started, to get a feel of the situation. Applying and interviewing was Sep-Nov of fellowship year, and I had a signed contract by Christmas. At my new job, my partner Anes/CCM guy just started his CA3 year, and he's been under contract with the hospital for about six months already. I will admit, though, that he's a bit of an exception, as he has strong ties to the region, and connections with the department.
While it never hurts to reach out early to sus things out, practices can change. Leadership can turn over, private groups can lose the contract or become hospital employees, the staffing model can change, etc. There was one group I had been talking to a bunch when I was active duty before fellowship. It seemed very promising, the leadership thought having a partner in the ICU would be a good thing, but ultimately when I interviewed, they couldn't sell the idea to the rest of the partners, and I wasn't offered the job.