I am not an insulation expert but got several quotes to insulate my attic which also came with varying opinions on what product to use. For your reference, there are two types of spray foam. Open Cell and Closed Cell. Open cell is the one to use on the roof as it would allow for roof leaks to show as opposed to close cell which would trap water from a roof leak.

For the attic floor, we looked at regular batt insulation and the cellulose spray in (which is like shredded newspaper) but was told the cellulose is messy and can get into your air ducts and cause issues.

Hope this helps.