Electronically fuel-injected engines don’t have a choke like old cars did, so the cold start process is handled by the computer. It detects the temperature of the engine (and ambient air) and then alters the fuel and air mixture going into the engine to give it the right ratio to fire up the engine. Cold starts generally require more fuel and less air than when the engine is at operating temperature.

The computer does all this via sensors so, if one sensor is not playing the game, the computer can’t alter the mixture and the car can be very difficult - if not impossible - to start. A good workshop should be able to sort this pretty quickly as the Magna’s engine is not an overly complex one and is a well-known quantity.

Clearly, there’s something inside the fuse box that isn’t enjoying cold mornings. It’s more likely to be a relay that controls the fuel pump (or some other vital system) as a relay has moving parts (as opposed to a simple fuse). Those moving parts could be weak or worn and might not be so keen to move correctly when the ambient temperature is low. It sounds pretty weird, but stranger things have happened.

It would appear the fluid has been overheated, so I would be doing a full flush of the transmission, not just a fluid change. I wouldn't bother about the coolant.