founders of MRCZ

As there is only 4 places on sheet I guess it’s limit.

Is there situations that player at the table have character not founder of current MRCZ?
Any way to become founder after creation of MRCZ?

By definition, you must found a MRCZ to be a founder.

And to limit abuse, there can only be four founders of a MRCZ.

If you want to be a founder after character generation, found a new MRCZ in play!

Correct me please, do I remember correctly that all players at table should be one MRCZ, so making new MRCZ is really making parallel gaming party?

Correct. At the start of the game you’re all part of the same MRCZ.