Tuscany is pretty big, so it will depend a bit where you are and how far you want to travel.
All the places you suggest are nice for at least half a day, even if you don’t look at the churches and museums. A little less known, but also worth visit is Viareggio.
The beaches aren’t great. My favorites are the wild places like suggested by matt_outandabout, or Castiglione della Pescaia.
The marble quarries at Carrara look interesting and offer tours. Still on my to do list.
Cinqe Terre is possible. My favorite bit is actually Porto Venere to Riomaggiore, which is outside the most popular part.
There are mountains and hills with excellent hiking. Monte Piglione is easily accessible without taking all day. Gondola at Abetone for getting higher without too much effort. Monte Farato if you want something longer. Dozens of others of course. Can be high and attract proper mountain weather though. If you do go into the Garfagnana then Barga is worth a stop.