I'll give it a shot.

#1 If a lot of leaves make it to the bottom of the pool, then a pressure side cleaner would be a better choice but you are currently not set up for one so it would probably be too expensive to change. A suction will work ok on leaves if they are small and if you have a leaf trap in line with the cleaner. I get quite a bit of leaves during leaf fall but the trap helps quite a bit. The cleaner only gets clogged once in a while.

#2 Some robotics are very good at cleaning. However, many require you to not only take them out when finished but also put them in and start them manually. Personally, I like to leave my suction cleaner in all the time except when swimming.

#3 No reason to stick with the same manufacture of a SWG. I would go by price and features. I have a Goldline unit and have been pretty happy with it for 5+ years.

#4 Most SWGs are pretty independent of the controller and have there own flow switches that shut off the unit when the pump shuts off. However, you should be able to wire the SWG such that it will shut off with the pump as well.