Chult and Port Nyanzaru: what are they trading? Where is coming from? What makes it desirable elsewhere?

We have been running Tomb of Annihilation and I keep wondering why Elminster isn’t in it

If one was wanting to run Tomb of Annihilation, how could I incorporate and adapt it into the Tal’Dorei setting?

Our fearless crew be settin’ sail from Waterdeep for Port Nyanzaru, how long would the journey take?