https://www.youtube.com/watch?v=tZvIw83uZgY watch this video might answer some of your questions. You are getting some advice from people who are not familiar with the motors you are looking at.
#1 fourstrokes start easier than 2 strks that's false. They are both fuel injected
#2 E-tecs use very little oil fill ups are few and far between and you don't need to worry about filters and getting rid of oil. And very little to no smoke.
#3 A four strk will be more reliable than a 2 strk that's false.
#4 People troll with their E-tecs all the time. Evinrude would have to have the worst engineers to not design there motors to work on pontoon boat. It's a pretty big segment to miss.
Both are excellent motors and both will run a long time. The video is pretty informative and will show you the differences under different conditions.