Congratulations on little Petrus
I will leave others to give you seating advice. What I do know having had to fly a lot with my 3 now adult sons when they were small and thanks to DHs work were were always up front we learned a lot
You have rightly identified the issue is their little ears and one thing you cannot legislate against is if they have small snuffle they are going to be fractious on take off and landing and there is nothing you can do
Yes, feeding them can me good if you can tie their feeds in, mine often would not, however I also found using a new dummy (comforter) for that flight works really well. When its new, they tend to suck more vigorously. I would not get the new one out until just before take off.
It was also an idea not to have them needing a sleep at take off stage as they would be more agitated then, I know its counter intuitive as you tend to think, have them sleepy before boarding and we will get a quiet fligth but we found the opposite so would encourage them to be wide awake at that time then after take off they would usually play happily, smile, hold court with adoring passengers and then might even be asleep at landing
Good luck and hope this helps