[TRWSHSHLX]

MS Word and Dropbox is one of the best options out there. The TOC function in Word can help you list figures, tables, entries, etc.

Alternatively, if you are going for a much more professional and serious look, have someone on the team that likes coding, and want more flexibility, I highly recommend LaTeX. It's not a programming language (it's a type-setting language) and lots of people in the academia uses it (especially in math and physics). It will benefit your team tremendously.