Amazon EssentialsWomen's Long-Sleeve Lightweight Crewneck Sweater (Available in Plus Size)

Why aren't any of the Amazon essential clothes in small petite women's sizes? It's so frustrating not to find my size.

Is it warm enough?

I can't tell the difference online between brown and dark chestnut brown. I don't want one too orangy, also not too taupe, which should I choose?

Are the solid colors opaque enough for patterned tshirts underneath don't show through?