no it's not

ed% in weapons
adds to base damage

ed% in non weapon gear (shield/helm/armor) would be 1.4*overall min-max damage

+15 max is same on and off weapon
same for charm, +3 max charm=+3 of maiming (?) suffix or jewel

edit : i'll check for you but only good way to get fcr for a zon for zVz is

10-11%ll /10fcr rings and 08 valk (30frw fcr ias)