You can still use latch in the middle seat as mentioned by using the inner latches of the two side seats.

Seems like the wise firemen agree that the middle rear seat is safer. While I understand it is not as easy to get to, keep in mind, easier to get to for you means easier for a car to get to in a collision as well.

By the way, if you get one of the car seats which have a base, you only have to do the seat belt/latch one time so it's really not a worry in terms of hassle.