L.H.
Hi there,
I've been a toddler teacher and professional nanny for 25 years and this is a very normal thing with toddlers and other people. I have a little "charge" who sleeps in only a diaper and has a fan going all night and that's comfortable for her where it would be too cool for some. At two, she's able to pull covers up over herself if she's too chilly so it's okay to dress her scantily and let her use the oovers if she wants/needs them.
L.