Hi 
I would like to know if it is possible to change back a gym into a stop and make another stop (in the same cell) into a gym.
Why ? It’s because 2 gyms in this cell are very very close and I would like to separate them better by putting one gym per crowed place in the cell.
Simple answer is No.
Pokemon Go uses some sort of algorithm that probably has some element of randomness.
If it was a problem it would be the Pokemon Go team that would need to look in to it. Wayfarer only creates a database of eligible wayspots. The game team decides what is used and for what.