As long as there is some green, keep going if not done.
definitely overfed, but really depends on how this stuff looked as it started.
cal-mag is possible, but often gets confused with p/k-toxicities or pH problems. read up and eliminate possibilities before adding anything.
Regardless, back off on nutes unless it takes an immediate nosedive. irrigate water only for a week if in soil, less if coco. if you have selected the most likely, do that, if it isn't harvest time by then... likely just going to flush and chop, i bet.