Zero chance Amen is involved for any deal for Fox.
I think you're right. Unless it's basically Amen and filler salary for De'Aaron. I think he's Houston's 2nd most valuable player after Sengun and he may close that gap quickly. He's elite defensively and probably the best athlete in the entire NBA. He has a long way to go, but I think he's going to be an absolute stud.
But this trade works and I'd strongly consider it:
Jabari Smith Jr
Tari Eason
Steven Adams
Jeff Green
1 or more FRPs
for
De'Aaron Fox
Alex Len
It also opens up a spot in the starting lineup for Amen by moving Jabari.