Is there elastic on waist band? I am looking for a non-elastic, non-binding waist band, similar to the smooth tops provided by Lululemon.

The top lays smooth, assuming it is not too small. There is not a clear elastic band, but has some give. If you are expecting this to be like Lululemon's the fabric is not of that thickness. I don't feel it is see through, but it is thinner and different that anything from Lululemon. That said I love them and wear them to work.

I am looking to purchase these on a "deal" price. If they dont fit can I exchange them instead of having to return and reorder them after the deal bec

I don't know what you mean by deal price but I think it says free returns for these particular pants on Amazon so I Would by with confidence .

I am 5’6 160 what size should I get?

The height doesn't effect the size since you cut it to fit. I'm 175 and got the Xl so for 160 maybe a large but check the size chart for hip dimensions.

What is the difference between the jean style 4 pocket and the regular 4 pocket?

Jean style pocket isn't as deep as the regular pocket. My pocket on the regular goes about half way down my thigh deep and I'm 5'6". Back pockets also have some good depth but more like Jean style.