Minecraft – still play Minecraft Xbox One edition if I’ve downloaded Better Together

Villager Farming is not possible on the Console Version of Minecraft as of version TU22/CU10.

Have a look at the changelog for Villagers. The PC version has the following entry, under 1.8 (14w04a):

Farmer (profession) villagers now harvest fully grown crops

Contrarily, this is absent from the changelog for the console version. In fact, villagers have not been updated since TU14, which is (very) roughly equivalent to PC version 1.3.1 according to the Version Overview.

You cannot access the content if your old account isn't currently signed in. You can only access the content if the account that purchased the content is signed in.

I did something similar with some DLC my friend had purchased on the same xbox. I signed in on their account, then signed in my account (at the same time), and I had access to the DLC.

Therefore, since the original account is not signed in, the xbox is reading that you (current profile) do not own this content.

EDIT: Here is a similar answer covering the requirements of the console and user licenses.