As far as I know -that temp range is for hatching female and mixed sexes of babies
I have read that lower temps equal darker babies and lighter temps result in lighter more vibrantly colored babies
I have no clue as to how it would apply to the Lavender pigment in Leos
I am sure that someone that is working with that color pigment in particular will be able to answer that
Well I wouldn't trust anything where you read that lol. Lavendor is a color morph. Those temps are the temps to hatch a mixture of male and females. Female temp is like 80-84 both 84-86 and like 86-88 male. I may not have those exact but those or close for being on the top of my head without looking it up.
It happens most often at those temps. However IMO genetics also seem to play a role in the amount of lavender coloration present. For example, Bright Albino's lavender bell line.
My 2 that are Hi-Yellow Lavendors were just breed that way not with any messing with the temps. My lavandors are Vince and J. I have pics of them in the gallery.