If the new stock is, as expected, operating a maximum half-hourly interval service crossing at a new Brading loop, there's presumably no need to retain the existing double track between just south of Esplanade and just north of Smallbrook.
Singling that stretch would allow the remaining track to be centred under the arch at Smallbrook Lane, to use the better span at Rink Lane (the down appears to have more headroom than the up), and possibly to ease the reverse curves in the tunnel (depending whether they're within the twin span or single span sections). If any of those are still needed of course.
Does anyone know whether this is feasible and/or intended? And also, whether the opportunity will be taken to remove the disused track from the pier? Though I suppose it may be more economical just to let that rust away (like the old tramway decks).