Regarding Referendum/Possible solutions for Council:
With todays' MC eV's bylaws, electorate is all community members. Councilors may keep that status as well as they're welcome to become regular members. So while it's absolutely fine that council may consist of non-members only, 2 suboptions open up for 1.):

1.a) Council stays apart from MC eV (not a body of it) and respectively can't have real power and responsibility (pretty much like Juiceme put it in 1.)

1.b) Council adheres to MC eV bylaws, becomes a body of MC eV (while the individuals may not) that can have limited power and responsibility as defined in the bylaws*. I'd rather call it option 4.) though.

* For now, this is defined in two paragraphs only:
§ 7 Board of directors:
(5) The Board of Directors executes the Council's and General Assembly's rulings.

and § 8 Council:
(4) The council has the duty to execute elections of all kinds. The council's duties, rules to announce council meetings, their proceedings and executions of votes are regulated by the Association Rules*.

* Association Rules alias General Regulations are not specifying anything beyond this (so far).

For the record, Full § 8 Council:
(1) The Council consists of at least 5 natural persons at least 21 years of age and is elected by the passive members' meeting.
(2) The Council internally votes upon a chairman and two deputy chairmen from who one is assigned secretary.
(3) On termination of individual council members, the duties of the retiring council member can be taken over by the remaining council members, provided that they agree. Alternatively, the council may supplement until the next regular election by council resolution from the number of active members.
(4) ^^...

me too!