Can a sagging rear cause the front tires to wear funny? If I recall right it can

If the rear were to sag and the front was to remain at factory height.........the front tires wouldn't know the difference.

But, what typically happens is that the rear drops and the front rises slightly and the change in camber can cause more wear on the outer edges of the tires.

I wouldn't think it's significant unless the rear is sagging quite badly.

It's a mix of outer wear (partially from cornering)
and choppy wear, which is new shocks needed??

The choppy wear isn't due to the sagging rear. Shocks could be the issue..........but, they'd need to be toast.

What else?