There is a connection between VMC and VFR, and IMC and IFR, but they are not the same things.
Flight under Instrument Flight Rules does not have to be in Instrument Met Conditions. In fact, most operators operate their flights almost exclusively under IFR, even in VMC. You can operate under IFR from take-off to landing and not once enter cloud, including to and from unmanned airfields.
Requesting and receiving clearance for a visual approach, does not cancel IFR. With a visual approach, the controller is responsible for air traffic separation, but the pilot is responsible for terrain clearance.
Filing as alternate, you must comply to normal AWOPS (All-weather Ops) criteria. That depends on the weather (TAF +- 1hr, etc) and facilities at your destination and your alternate(s).