"Can I conclude that the treatment of the Taxpayer's Distribution is correct."

For each condition (taxpayer or spouse, year, account type, basis at the time of the distribution, the amount of the distribution) you need to work through the details. I previously provided a link to the MA listing for all types of retirement plans and accounts and for how they treat the various types and taking into consideration the type of distribution:

https://www.mass.gov/service-details/view-non-government-pensions

No one except for you has all the required info.