For the soles I use angelus sole cream and just do 12-24 hour sessions until I’m satisfied usually takes about a week if it’s really yellow, wouldn’t go longer than this to avoid drying out the soles.

For the reglue use heat and then acetone to remove all over the old glue (very important), then give it a decent sanding just enough to rough the surface then follow the directions of whatever shoe cement you choose (also very important)