The He-111 would definitely be of GREAT value. I place it third behind the G4M and Ki-43.
However the Ju-52 is probably about as low on the priority list as a plane can get, just BARELY rating above the P-63. In the Mains, the Ju-52 is basically an even slower and more vulnerable C-47. Some had a gun, but you're talking a single 7.7mm. Ask Kate pilots how effective it is. And unlike many aircraft that do or would see very little use in the Mains, the Ju-52 would have very limited usefulness in special events.