what if my mother ends up taking stopover in London instead? Does your answer change because the 'long' flight is being split up? I can't imagine the feeling having to wake my kid up for a stopover
It's more of a tossup.
If your kid is up, than a stopover gives him a change to streatch his legs and run around a bit.
If hes crying alot, the stopover will have you seated near different people who havent spent the last 6 hour tolerating it.
If you have a bad seating situation (like the guy in front of you is leaned back and you don't really have any room on your lap for the lap infant...), the second leg will likely be better...also can depend on whether you will be paying to garantee a a bassinet...
If you have a place to put your baby, and it and the toddler are sleeping... yeh, it sucks to wake them up.
How much hand luggage your taking can also be a factor...if you have a sleeping toddler and infant, and you have three carryons, plus 5 personals, plus more stuff for the baby...you've run out of two peoples hands a long time ago...
I'm not a navi...
Personally, I would take the stopover with the extra hands...