I had the same issue. You don't want to use loopbe1 because of midi feedback errors which will occur if you try to move multiple faders at once. Instead use loopmidi and change the feedback alert to 20,000 notes per 5 sec.
Then in midi ox using data mapping change one of the mpcminis to output all from channel 1 to 15. 15 is a very uncommon channel among static channel daw /midi controllers.
Midi input apcmini 1, output to loopmidi out in midi ox.
Then in mpctools remap the first apcmini to be 'loopmidi in' input.
The problem lies in the order you open mpctools, loopmidi and midi ox.
Message me if you have any questions because this is my exact setup.