It's intentional really, otherwise the UFP can expand far too fast.

You can also use the regular subject types and just set the agreement to allow expansion.

Is there a way for me to absorb the entirety of the members. If not is that an option that you may look into. Nothing permanent I would just like the option to change the membership agreement

No, members are set up the way they are for a reason.

im trying to get the federation to form. i am curious if it changed from before.

Heh, without knowing what your "before" is, that's going to be hard to know.

Forming the Federation, and a bunch of other stuff, is handled by the player running the appropriate Council Agenda.