Ladies Zip Front Boilersuit Workwear Boiler Suit Coverall Overall Womens Girls (14 (38" Chest), Royal Blue)

If I want to wear clothes under the overalls should I get my normal dress size or will I need to go up a dress size? Thanks

Is it waterproof?

How do I find out the leg length?

I'm 5ft 10 will it fit me I like it baggy so I picked the 16 chest size ?