WordPress Template Advice Required

I am looking to develop a website based on wordpress. This will be a website with 1) simple 4*2 grid layout and top banner 2) Use Wo-Press since there will be an ecommerce element 3) Very mobile friendly and responsive, even mobile native since ~95% of our customers will see it on mobile 3) Out of 4*2 grid – 3 sections in will have videos 2) 2 will be images 3) one will be a shopping block 4) 1 text blog 4) 1 section will be a moderated chat room. So all widgets will need to be added, if not there. I am aware that even the best template would need to be modified. But I am looking for somebody who has done tonnes of wordpress websites and can suggest me the best templates to get free or buy. It will save me some time and am ready to pay for that advice. Depending on my comfort I am open to give the modification work to the person going ahead.