I'll just respond to part of your inquity.
Since you are over 59.5, on the Roth....
1) distributions of contributions are tax free
2) distributions of conversions are tax free
3) distributions of EARNINGS are subject to income tax UNLESS ANY ROTH account you own has been open for 5 calendar years. So only this bucket could be subject to tax. And since the IRS presumes ALL contributions and conversions are distributed before earnings, it is highly unlikely (but possible) this bucket would ever be taxed. This never resets for new contributiosn; simply the earnings are tax free once any Roth you own has been open for 5 calendar years. What year did you open the Fidelity Roth IRA?
4) there is never a 10% penalty on a distribution since you are older than 59.5 years old/
why do you beleive you need to covert ALL the money AT ONCE to a Roth. The tax bite is probably going to be smaller is you spread it out over a few years. Since you are 65 and presumably on Medicare, you will become subject to IRMAA, which is a stealth tax, that can sigficantly increase Medicare premiums for the one year. If you have an additional $200,000 of income for one year due to the conversion to a Roth, and you are single, the IRMAA premium is approximately $442 per month for that one year (and that is on top of the $164.90 per month normal premium).
