Financing the purchase of a single-family home: Lower interest rate or longer term?

So, seriously: Where is there even the slightest hint of risk in option 1? The house is currently worth over 600k. Even if the market were to crash and the house were worth only half in 15 years, you would still be at about 50% loan-to-value. And the 150k would be worth only around 120k with an inflation rate of 1.5%. Your wife will most likely be able to cover that on her petty cash alone.

Just mathematically, the interest rate would really have to get high to not be able to pay off the 57k difference in the next 5 years, something around 6% maybe? If additional repayments are planned, that shifts it even further.

For me, long-term secured financing would be more important - a 0.25% interest surcharge is nothing at all if you then have to take out a follow-up financing at 3, 4, 5, or even more % in 15 years. No one can say for sure what interest rates will look like in 15 years, how house prices will develop in general and especially in your area (i.e., what percentage of the house value you will have paid off in 15 years), etc.
There are good reasons to predict an inflationary development in the next few years, but how politics will react to that, how the political majority relationships might change, etc., no one can say exactly.
15 years ago, the current interest rate level would also have been considered absurd.

At least 15 years, very nice high repayment. Have you asked an intermediary?

It depends on whether you can live with the remaining debt for 15 or 20 years if the interest rates are between 4-6%. Or whether by then you have enough money to fully repay it either through saving, inheritance, or other sources, life insurance, etc.

I would consider long-term secured affordability more important - a 0.25% interest surcharge is nothing if you then have a follow-up financing in 15 years at 3, 4, 5 or even more %

Yes, it is, because the interest surcharge increases your costs in the first years. That sounds little, but with that loan amount it does add up. I calculated it for us back then and the point where the longer fixed interest period (without special repayments) would have been more economical would have been reached at about a 3.8% follow-up interest rate. We then looked at the interest rate tables of the last 20 years and decided for ourselves that we consider it unlikely that the interest rates will be at 3.8% or higher after 15 years. Of course, it's not impossible. It's your decision: risk willingness VS. probability.