This would be a tough one to fly. First, as @misscrystal mentioned, it would have to be a pre-approved website and even then it’s risky without written permission from Customer Support. Second, if you have any link or mention on the site of how to contact you outside of Fiverr, you’ll be banned when caught. Third, if you have any payment options for people to become members besides the exclusive Fiverr membership, that’s an automatic ToS violation.
Those are just the ones I can think of without re-reading the ToS. If you are lucky enough to get enough sales to get to level 1 or more and then get banned over ToS, that would be a tough break. I’d definitely run it by Customer Support, not just the forum. Your definitive answer will be there as long as you tell them the site name, exactly what’s on it, why it doesn’t break ToS and what your gig description will say in the final version.
As a side note, I have only written 2 e-books (ghostwritten) and a lot of short stuff for various publications. I am a member of several really good free author/writer groups and wouldn’t pay for one even at five dollars a month. That’s just me, though, so others might!