Church Warden vs Reed Hut in Round 14
The Unofficial Agricola Compendium doesn't mention this combination explicitly, but I think the answer is option 3 from your list.

Option 1 contradicts clarification B from the Reed Hut section, and both options 1 and 2 are contradicted by clarification E:


  Reed Hut (K138)
  ...
  B. The occupant of the Reed Hut is placed after your family members [ref]...
  ...
  E. You can move this person into your home with a family growth action later. That family growth action must be taken by another family member. [ref]


Both reference links are from the compendium, but seem to be broken.

For completeness, here's the ruling about newborns and the Church Warden in round 14.


  Church Warden (I227)
  ...
  B. A player who only gets a 5th family member in round 14 does not receive the bonus points, unless the new family member takes an action that round because of the Adoptive Parents.


The one thing I couldn't find was whether you'd get Church Warden points by taking an action with the Reed Hut person.  I would say that you can, based on the card's wording, as I think that although the Reed Hut person is not a 'family member', they are a 'person':


  At the end of the game, any player who performed actions with at least 5 people in round 14 receives 3 bonus points.