Status check

This might belong more in coastfire, but ultimately I'd like this community's input.

My wife and I are both 39, two young kids. House paid off (500k equity roughly). Cars paid off, though I'll probably need to get a new one in the next year (I'm over 200k now). Kids' college already funded thru 529s. Both kids out of the house in 15 years. Zero debt. Roughly $80k in annual expenses, though that's going to drop by $10k in a year when our youngest starts school, but I still want to assume $80k annually. We don't live extravagantly but enjoy travel and don't really intend to increase our spending other than maybe a big splurge trip every few years.

Liquid assets... $1.1 million in taxable equity account that tracks the market well. $90k Roth (I know, not really totally liquid). $600k in bonds and MMA yielding 5%. We also earn about $20k annually from our stake in a holding company. We've also got about $400k cash, but we're looking to do an expansion on our house that will cost at least $200k (let's call it $300k to be safe).

I recently sold my business and am taking a break. I intend to start a new career next year earning roughly $80k. At this point, I'd like for my wife to be able to retire if she wants. As far as I can tell, we'd be fine. IF we need to supplement my income then we can pull some from the MMA while our equities continue to grow untouched. I'm also thinking of moving $300k from the bonds account into equities, which still gives us almost 4 years of expenses in our reserves. I'm fine to work another 10-15 years and let our money grow.

Question 1- Am I right in thinking my wife can retire at will as long as I work another 10-15 years?

Question 2- we're considering building a small rental property on the backside of our property that would cost about $300k and yield roughly $24k annually. We could always sell it later, and we live in a desirable part of the country so I'm not worried about losing money. But how would this change the calculus in terms of wife's retiring at will? If we pay cash, then I suppose we'd only have $100k extra to devote to equities if we want to keep $300k in the MMA reserve. This would slow the equities compounding/growth, but we would have a passive income source as well that we could later sell. In short, I'm not sure if we should bother with the rental or just put that money in equities.

I understand there are lots of ways to approach this, so I'm interested in your thoughts. Many thanks for reading my novella.