the poor girls aren't even allowed to choose their own leotards for gymnastics, because they have to be in their assigned colours. the world wouldn't end if two of the gels chose the same colour, or if Lottie chose pink, and Annabella chose yellow - which, generally, seem to be the colours they actually like.
and as for the spaghetti, "spag bowl"! is a meal that is served to the kids pretty much every other night - and at least multiple times a week, so if Lottie has specifically been asking for spaghetti for over a week, and has been made to to wait a whole week to be given a meal they usually eat multiple times in a week, it very much implies that they purposefully didn't serve it just to spite her!