Hi Diana -
I think you get different viewpoints on your plan but ooof, it's a lot of moving around and quite a number of short stays. Keep in mind that you can easily kill 1/2 day every time you make a move?
It would be most accurate to count the number of nights you have to spend in Italy versus days. How many nights do you have on the ground in Italy?
Rome: arranging your trip to miss the Easter holiday is advised.
1 night in Venice is only 1/2 day; not much time for a city which deserves at least 3 nights. I'd take it off the list and add that day elsewhere.
I'm confused by Florence; are you staying 2 nights or 3? 2 nights will only give you one full sightseeing day. Same with Como and the CT.
2 days Cinque Terre (hike between villages)
When most tourists say they want to "hike between the villages" they mean doing it on the most popular route: the Sentiero Azzurro ("Blue Path"). Note that the legs between Corniglia>Manarola>Riomaggiore have been closed to damage for some years now and are not expected to open in 2018. There are other routes in the park but they're longer, more strenuous, and shouldn't be tackled if it is or has been very wet. Reference the park's website:
http://www.parconazionale5terre.it/Eindex.php
This page is the most useful:
http://www.parconazionale5terre.it/Eindex.php
Right now the entire length of the "Blue" (SVA2) is closed but that's not unusual over the winter.
Day 14-17, Amalfi Coast (Positano etc... beaches,relax and chill for
4-5 days. Take train back to Rome- fly home next day.
Again, count your nights and not days? Positano is a long way from the CT and will use up most of day 14. If you have to return to Rome on day 17, you'll only have have 2 full days and fractions of two others in the Amalfi area, not 4 or 5.
We all travel differently but I'd probably consider dropping either the CT or Como along with Venice and shuffling the time between the remaining locations.