We have been bringing our babies (2 under 2) and toddlers (I have 3 kids and they are 2 years and 52 weeks apart - not twins) transiting and sitting in Y, no issues at all. Bringing babies are easy as long as you can breast feed. It's worse when they started to walk, but then with good preparation it was highly doable even in Y.

Our babies were really not happy about the bassinet, so we carried them until they felt deep asleep and put them into the bassinet. They seemed to have a button on their back and if it touches a bed they would wake up. We saw no reason to fly C as we couldn't both lay down and sleep anyway.