It is possible with MSFS to use Latching Buttons for a Button Box or have the buttons be momentary Buttons? And if Latching do they have to be On/On or can it be On/off buttons
I use latching switches in on/of, for several commands in FS2020. It depends on the UI board used on whether you need to use toggle or specific position commands. Is the board sending a single pulse with every move of the button, or is it giving a continuous signal when in the “on” position.
Also, is your button 2 or 3 prong?
I have no Buttons yet. still in the planning phase 
But perhaps I go for this one. is On/off momentary
(german site)
and perhaps this one:
I use latching switches in combination with a Teensy 4.1 and Spadnext. The programming triggers on the raising and falling edge and this works fine.