With your Subs all gathered together in one place, you are not getting any benefit of multiple low frequency sources as they are considered Colocated and thus operating as a single source.
That there are no phase issues between the different designs is nice. Not everybody is so lucky.
I think the answer to your question is more one of personal values and what you plan to do with them in your room.
If it were me, I would do a minimum of two subs and find the two best places in the space to get a more even Bass response across the seating area. If you add a third, then placing that in a third best location will improve Bass response further still.
You could try it with the Subs you have since they aren't creating any Phase problems, seemingly, though that may change as you separate them.
Again, it is your room and up to you about how you choose to tackle the situation.
