I’ve been a serial house hacker in the greater Boston area so happy to connect and share some lessons learned.Multifams inventories are quite low depending on your budget and location preferences.  

Meet with a local banker & schedule a time to talk with a mortgage broker, they'll give you at least a baseline of what kind of down payment options and rates are out there.After that, if you're still wanting to research more creative options, do some looking into seller financing (a very hot topic with good, and bad, advice out there), look into private lenders, and commercial financing options.If you're wanting to live in 1/4 of your quadplex, then conventional residential loans may in fact be your best option as you can purchase that with a fannie/freddy loan with very low down, and use up to 75% of the income from the property toward your own income. 

We are not likely to see rates that low again in our lifetime.

I was initially drawn in by the low fee, which has since fluctuated, but may still be the lowest out there.

There are other loan products available that are still a low down payment. 

For example, if she can't visit the property, is she good at record keeping (so everything is organized at tax time) or finding vendors, comparing product prices, finding free or low cost items on Facebook marketplace to improve the rental)3. emergency fund.

Until 2018, when it was closed due to low revenue and high maintenance costs 2.

Preferably low or no money down as best seller would be one only interested in the monthly incomeI then sell said first property and take that cash to buy the investment I am really wanting and I get the terms I want.only thing I don’t know about yet is, how to dodge the tax on the sale of the initial property?

Rents are generally low there as well, but definitely stable.

Multifamily doesn't need any more pressure/demand since cap rates can really get low when too many people pile in, but I have to say that commercial real estate (including large MF) and other types of passive investing (mobile home parks, storage, etc.) can really make like much easier.