EZ wiring connections

EZ wire should have a customer support number. Probably would be a question for them.

Taking a guess, the fan-fan wire is likely designed to work with the fan pwr wire and a switch. If you have things routed differently, the wire may be redundant.

Other wire sounds like a power source for your heater fan or for an application you don't have. These kits are universal in design and it is not unusual for extra circuits like this. Don't connect them if you don't need them, but be sure to insulate the unused ends and dress them out of the way.