I met with the project team recently; they will be updating the official page soon, but until then read on for updates...
Jetty will be open by 'autumn 2020' (ie now) with a deadline of 21st December.
The Newmarket Road underpass is aimed to be done Spring 2021.
The whole of Phase 1 ( up to Coldham's Lane) is planned to open Autumn 2021.
The bridge will be finished and hoisted in soon; the reason it won't be open until a year later is that there are various works on the banks and the approaches/steps that will still need finishing before it is accessible.
Fen Road access is still planned to be via the existing cut through, with a small build out to improve visibility - I'm awaiting more detail on the design, and am meeting the project team to discuss linking up with the 71-73 fen road developments.