Lets say Han with Esteemed Leader is near Chewbacca and 2 units of Fleets.

Chewbacca can roll for 3 of Hans wounds, but can both of the fleets also roll for a wound each since they now have guardian 1?

Yup! Each unit with Guardian can redirect up to X of the hit results. Note that they can only take the hits, not the crits.