The Turbo Maxx vent cover and fan
is 32.5" from the front of the vent to the rear. The means it will need 32-19 or 13 inches of clearance to the rear.
As you can see from the product's home page, the fan is reversible.
I've got a similar problem with a kitchen vent on a '75 that has a plastic center that has cracked. I was thinking of replacing the vent with a Maxx Air but the clearance to the rear doesn't look good for that either. It also strikes me that there is a need for some clearance to help air flow as well. So then I looked at the front vent and noticed the TV antenna might be a problem ...
The Turbo Maxx should not have any impact at all on the inside vent cover and light situation except that you'll need to tap the power line for the vent fan. You may need to do a bit of finagling in placing the controls, though.
The Maxx Air vents and covers seem well made and do a good job. There is some speculation about the design restricting air flow a bit but, to me, the benefit of not having to worry about rain incursion is worth a bit.
also- I think a thermostat is worthwhile. I set it to 90-95 or so when not using during the summer and it helps keep the heat buildup down. It has also served useful in shutting the fan down at night after things have cooled down so I can leave it on and not worrying about getting up in the middle of the night to keep the desert cold nights from getting too chilly.