is he eligible for this fall, or has the NCAA not ruled on his situation yet?

Either way this was a huge get for ND. I do not see how plays this year but I am excited for his future.

Yep this is a big addition to the 18' squad. It's essentially signing a S in the 18' class, that will be ready for PT at the start of Fall Camp. With as well as Robertson played/looked this Spring, Elliot's progress, the signing of Alohi, and potential signing of Allen. S looks pretty healthy going forward.