Can Leaf cells use WatchMonPlus
Yes, whilst WatchMonPlus was designed to solve the problems connecting to a shared loom, any Lithium cell can be connected with a WatchMonPlus.
Here is a typical wiring diagram to control 24v contactors and fans using a DC-DC converter. Note DC-DC is only required if peripherals such as a fan are other than the pack voltage but if used should always be before the power.
Note: provided you are using the same battery chemistry and Amp hours, Leaf cells or other good quality cells can be used to make up the last 2s to increase to 14s where your shared loom cells are at 12s,