Ok, the first problem I see is that you have both devices and the Mastermind all on the same MIDI channel. You need to change the DD-200's MIDI channel to 2 in the Devices tab, and also change the MIDI channel to 2 on the DD-200 pedal itself (consult the DD-200's manual for how to do that).
In MIDI settings in the Mastermind editor, set MIDI Receive Channel to None. With the way it's set, you will probably encounter problems. Don't enable MIDI Receive Channel unless you want to use a computer or other MIDI controller to change presets on the Mastermind. And, if you do want that, you should set MIDI Receive Channel to be a MIDI channel different than what your other pedals are using.
Once you correct the MIDI channels, you should get preset changes to work. You don't need to add PC actions to to a preset, the preset numbers chosen in the PC Numbers section of the Presets tab will be sent to their respective pedals.
Here's a video I did on setting up presets. It may be helpful:
Basic Preset Editing
Regarding the using of the Nixie editor: MIDI Thru or "MIDITH" needs to be set to MERGE on the Mobius. Also, you need a connection from the MIDI Output or MIDI Thru of the DD-200 that connects back to the MIDI Input of the PBC. Otherwise, the Mobius can't communicate back to the editor.
I'm not sure why Loop 7 isn't passing signal. Does the loop work if you unplug the cables from send 7 and return 7? Check both cables and make sure they're good.