If you're in the 12% bracket now it probably makes sense to tax gain harvest up to the top of the 0% capital gains bracket now. Also consider your tax rate now vs after you move to CA. It looks like AZ is quite a bit lower.
Other than for businesses (the pass through deduction), people with dependent kids (changes to the child tax credit) or people who itemize (fewer eligible deductions) the new lax law isn't all that different except the rates have changed, so if you like messing around with spreadsheets you coudl probably whip something up. Single filers get a $12k standard deduction, married get $24k. Here is a good set up tables with both earned income and capital gains brackets
https://www.nerdwallet.com/blog/taxes/capital-gains-tax-rates/. It's a little confusing because the top of the 12% bracket and the top of the of the 0% capital gains bracket don't quite line up anymore, so there's a $200 overlap between the 12% bracket and the 15% capital gains bracket.
I have heard that dividends tend to be about 2% for VTSAX. I wouldn't think that would be exact, but a good estimate. My experience is that all dividends show as unqualified until the brokerage issues tax forms, so I expect most of the unqualified dividends you're seeing are actually qualified. You can look at past year 1099's from your brokerage and divide qualified dividends by all dividends to find a ratio you can use to estimate.
What I don't understand from what you're saying is how you propose to transfer money into your Roth from taxable? Once you no longer have earned income you can't contribute, so what are you going to do with the money you get from selling stocks in taxable as you tax gain harvest? And where do you get the money in Roth you'll use to buy more VTSAX?
You'll need to check what your cost basis tracking method is with your brokerage (and maybe change it), but if it's Specific Identification you should be able to select precise tax lots or parts of tax lots when you sell. If you purchased any of your lots before 2012 they may be "uncovered shares" which I think have different rules about how the brokerage was required to track cost basis, so you might run into issues there as I think the investor was expected to do their own tracking. It sounds like you're seeing the cost basis information, so it should work out one way or another.
Remember to consider ACA limits as well as tax brackets if you'll be getting health insurance that way. Here's a good post on that:
https://rootofgood.com/affordable-care-act-subsidy/ -- remember to look up the current income limits, but the thought process should be the same.
Cost basis is "stepped up" at death, so if you really don't expect to need the money in taxable none of this really matters as your heirs won't pay tax on the existing capital gains anyway (at least under current tax law). Converting traditional to Roth still makes sense as Roth is a better thing to inherit (inherited Traditional IRAs have RMDs as soon as they're inherited regardless of the heirs age).