I'm leaning towards option #3. Just not is a question of budget and down payment. I was initially going to put down 20% cash from a taxable purchase at a higher expense ratio (before I knew what I was doing). I'm wonder if it's worth it to put more down to keep my month expenses lower so I can re-save and have a lower FIRE number? I have about $300k in the taxable. Each 100K should take off about $500 on the mortgage. Looking at around $500K and likely will have a small HOA since I can't afford single houses here.
Putting more down to have a lower payment doesn't lower your FIRE number. It just moves around where it is allocated. The payment itself doesn't matter from a required stash perspective. Because the loan length is finite you typically only need enough to cover the remaining balance of the mortgage. So putting more down just means less you can invest.
There are other reasons to try and lower the payment, however. Once you are retired and drawing on retirement accounts if the amount needed to cover the mortgage is high it can push you up into higher tax brackets and/or disqualify you for subsidies. Though there are ways to mitigate this (e.g. refinance at retirement).
We personally put down 20% for our last house. It's a good number to avoid being upside down and avoiding MIP/PMI payments while still using the power of leverage.