OK, but you still only need one mosfet to shut down the battery when voltage is to low. The LTC4412 datasheet shows how that should be arranged.
Where are you getting the reference voltage for the comparator? A comparator and logic-level mosfet would be pretty simple.
Have you considered the LTC1998, which is a single package designed for this purpose? I am sure there are other devices that do the same. That part number was just the first to pop up.
John