1) my 2.5 years of retirement has been great. The market has been strong, so it has been working for everyone.
2) That is for you to decide. It is more conservative than most.
3) This long article is a must read:
The Safe Withdrawal Rate Series.
4) Health insurance is not really a gotcha. It is just expensive if you do not get someone else to pay it (employer or government subsidies). I budget $40k/yr. It is the price to play the retirement game.
5) There will be down years. No need to cut spending unless things are worse than you planned for. There are many approaches to this. I think a lot of people use a similar strategy to what they used pre-retirement. I know I do.
6) Debt is a financial tool. It is neither good or bad. You have to decide what you want to do. I chose to be out of debt by 40 and never go into debt again. My decision goes beyond purely financial. We are not just financial beings.
I have had no surprises in retirement. I was on Bogleheads for 12 years before retiring. I think that made all issues known. I lurked on here a few years before retiring.
Going into retirement I mainly had to figure out two things: health insurance and making tax payments. I will start Roth conversions this year, but I know how to do that. It is very similar to backdoor Roth.