I think it would certainly be interesting to experiment with. Mihocek does seem to thrive when he gets to play alongside Cameron/Cox, but given Freddy is a bit taller than him maybe he could occupy that role.
Would AJ be the ruck backup? I never thought of it as a potential tool of his, but he looked at home in the VFL playing the ruck. He's 193cm and 87kgs, so not tiny (same height as Chris Dawes!) and is a monster athlete
Good way to ruin him, let him just play fwd.