I would simply apply 6.3 in majirel with 8.5 volume developer from roots to ends after consulting with the client and informing them of a plan where the old highlights will start to pop back out within 2 to 3 weeks, at which point the hair will be a perfect match to the photo, and retouching in the future will be simple.
(there is enough ammonia in the majirel 6.3 to create a nudge of lift and slight exposure of warmth with the 8.5 volume to create a near perfect match to the base shade in the photo. I would then follow up retouches as the highlights begin to resurface with 6.3 on the roots, free hand painted highlights with either .00 and 20volume or a very mild bleach, and toning with 8.3 in richesse.)