I only know that the whiter the color, the fuller and healthier the larvae are. The yellow larva means that it is ill and probably can't get out. If the larva always crawls into the soil, it means that it is very uncomfortable and will get sick.
And the pudding cup is too small. I put them all in the lunch box. Mine was put in a lunch box, and the corners were broken when pupating. I suggest you put it in the fish tank.