You don't even need to use the Elder Gods to run Resident Evil with CoC rules; all the RE monsters are genetic mutations (even if they do appear to be Lovecraft rip-offs). There's no magic involved. Nothing says you can't have Umbrella working for the Elder Gods, however, and that might be even more plausible (as their experiments are scientifically impossible in the real world).
I would think a Spycraft/CoC mix would present the most accurate recreation of the Resident Evil series, with characters playing STARS team members, mercs, or Umbrella agents. The scientist class from Pulp Heroes would be a definite one to include for those Umbrella mad scientists!