take a peak at my rough itinerary and critque?

A day trip to Pompeii from Rome can be done but it will be a long day. Then the next day you are again heading south in the direction of the AC. Why not just leave Rome, head south to wherever, and visit Pompeii from there? That would appear to eliminate a long trip back to Rome and free up more time to see and do rather than just get from Point A to Point B. Just a thought.

There is a luggage storage facility at Pompeii so stop there enroute to the Amalfi Coast.

For transport ease and access, Sorrento would be the best choice for a base ( vs Amalfi or Positano)

Make your trip to Pompeii from your base in Sorrento

I think you have laid out a great plan, time in each location looks ideal to me at least.

I agree with others that mention to do Pompeii for the day but then head to Sorrento from Pompeii instead of back to Rome.

Since that revision would give you 6 nights in the Amalfi Coast region, you could definitely split up your bases there.
I prefer Positano so would do Sorrento for 2 nights and Positano for the remaining 4 personally.
That is actually exactly what we did on our trip and thought it was a good mix.
We combined that trip with Rome as are you (we did not go to Venice then but went to Venice last fall)
You can daytrip to Capri from either town provided no storms at sea are limiting the dock at Positano.

Positano is likely a better base for your AC hiking day.

Sorrento is better logistically for most everything, I won't argue that point and probably cheaper than Positano but is not really on the AC and I preferred staying Positano of the 2 towns.
Ravello and Capri are other options where you could stay overnight which would both be wonderful as well.

thank you all for the very useful insights!! I will definately not do pompeii from Rome
Very helpful

more questions to follow as i plan !