A head that's full of dreams

A head that's full of dreams. = Caput quod est plēnum somniōrum.

Caput somniōrum plēnōrum est. = There's a head of satisfied dreams.

A head full of dreams. = Caput plēnum somniōrum.

Cum somniō plēnō caput est. = A head is filled with dreams.

I'm just not sure how to properly connect an adjective to a genitive noun, or if the adjective goes with the nominative when there's a genitive in the sentence.
And does case, number and gender still matter when connecting an adjective to a...

A head that's full of dreams