Could you post more pictures do the first one? There is not enough detail there to be sure but it may be a walnut.
I agree the 2nd and 3rd are Rhododendrons; the 3rd is one of the types referred to as an "azalea".
Ask your son to get the picture with the light behind him. The pic in the first post is a silhouette, and does not show as much detail as it could.
A picture of the main trunk showing the bark could help, too.
If there are any fallen fruit that have lasted over the winter that also could help.