This was true to size for me. I am 5’4”, 127 lbs and typically a size 4. I purchased the small and it fits great.
No, you will need to wear a sports bra.
The body length is : XS: 23.25 S: 24 M:24.75 L:24.5 XL: 26.25.Hope my info will be helpful for you.
I'd wash them on the delicate cycle with cold water and air dry. I also use the blue version of active detergent which is made specifically for workout clothes.