If you are letting your female incubate her own eggs, I would not try and feed her.
Not because she won't eat (which she may not), but because any jostling of the eggs she is carefully protecting while she is eating, is a bad idea.
And as for the other female incubating another female's eggs, I would not recommend it.
Females let eggs roll out of their coils if there are too many, and if there is something wrong with them.
If you put MORE new eggs in there, there is no guarantee that the incubating female will take them, much less take care of the ones she currently is coiled around.
Get an incubatorMuch less stressful (to a point).