It is complicated. I think I mostly understand my own situation after being FIREd for 8 years. But the tax laws change over time, and my situation changes over time, and my understanding grows and changes over time - all of which means it's a moving target.
My comments:
1. It's helpful to have some margin and wiggle room in your retirement plan. This will reduce the amount of pressure on you to do everything optimally. I was very prepared, very knowledgeable, and I still wasn't optimal. You won't be optimal.
2. Technical nitpick, you wouldn't have $36K in capital gains. You would have $24K in capital gains and $12K in qualified dividends. The latter are taxed much like the former, and I think that was your point was the taxability.
3. Assuming you live in the continental US, it looks like you'd be at about 262% of FPL ($65,200 / $24,860) (
https://obamacarefacts.com/federal-poverty-levels-for-aca-coverage/). If you can get that down to 250% of FPL, your family would qualify for Silver CSRs, which might be marginally beneficial.
4. In that FPL range, you're going to lose your subsidy at about a 15% rate (
https://seattlecyclone.com/aca-premium-tax-credits-2021-edition). It'll be something to pay attention to.
5. The rules for the child tax credit keep changing. This year, some of it is non-refundable, and some is refundable as long as your income is high enough. What I would probably do (and in fact did), was to do a pro forma tax return every December and increase my income (via Roth conversions) until my child tax credit and any ACA subsidy repayment were used up.
6. The saver's credit requires putting money into (generally) retirement savings. You're wanting to FIRE and spend from retirement savings. It's nearly impossible, as far as I can tell, to do both at the same time. I'd give up on trying to get the credit personally. It's small and your situation really doesn't apply.
7. The rules for EITC change sometimes as well. If you have more than $11K in investment income, you would be disqualified, so under your current plan you wouldn't be able to qualify (you're at $36K with the numbers you gave). I'd give up on this credit as well.
8. I don't understand about how working would make your cash run out more quickly. If you were working a bit, and/or got any of the credits, those both would create spendable income, which would reduce the draws required on your savings and retirement accounts.
9. I paid off my mortgage, mostly for cash flow and simplicity reasons. And I did get some nice savings as a result (mostly FAFSA related) and enjoyed the simplicity. However, in retrospect it probably reduced my net worth, because the arbitrage opportunity between my 2% mortgage and my ~10% stock returns over the remaining term of my mortgage would have likely outweighed the tax benefits. With your 2.5% mortgage, were I in your shoes I would keep it, pay the minimums, and work the plan assuming that the mortgage stays. (I don't have the numbers to prove it's better that way, that's just my gut feel. Your situation would be different anyways.)
10.
@Josiecat23503, yes, you do have to meet one of the exceptions otherwise the 10% penalty would be due if withdrawing prior to 59.5. Roth ladder and 72(t) are two exceptions, there are a few others -- see IRS Form 5329 for a list.
11. I prefer a Roth ladder to a 72(t) at age 45. Too much can change between 45 and 59.5 that is hard to predict - kids' college, going back to work, inheritance, investment returns, lifestyle changes, etc. I like the Roth ladder for the increased flexibility. But you do need to find a way to get it "primed" with 5 years of living expenses, which can require either planning ahead (which is what I did) or financial gymnastics for the first five years (which is possible too).
12. Don't forget state income taxes if any, and FAFSA effects when the kid gets close to college age.
13. I'd work on reducing your expenses. Every dollar you don't spend is $25 you don't have to have saved up.