Ideally the owner would handle everything and would have no need for a property management company with only this single duplex in their portfolio. 

There are many reasons that adding a single ADU in southern CA is a less than ideal RE investment (i will post a list at the end) but the negative initial equity is a primary reason as the initial negative equity position consumes the initial cash flow and can take many years to recover.As for converting your home to a rental….

Yes, looking for another property now, ideally one where I don't have to live in a closet

A 4-plex would be ideal and you could play around with doing 1 long-term, 1 mid-term, and 1 short-term, plus you, if it works on your area to upgrade your income.

Zillow is not ideal because this is a monthly furnished rental - which Zillow doesn't have a specific platform for - but that's what has worked for me up to now. 

Class A properties can almost auto-run themselves, but Class C/D properties can take a LOT of time.At one point I was self-managing 25 Class A & B properties and could do it despite working 60 hours a week at my day job.

Ideally, we'd like to acquire one or two duplexes that meet the 1% rule and provide us with $1,000–$2,000 USD per month after property management fees and other expenses.

To help support that avatar, try and have on-site parking and ideally a place where a large work truck can be parked without issue (think fully decked out F-350). 

Some carriers require limited water damage coverage depending on the age of the property and age of utilities.I would recommend at least 25% (ideally more) when possible and if you're limited to 10% you should make sure you cannot purchase another policy for a similar price.

This property would be for my in-laws to purchase and move into, but I'd ideally dovetail any success into finding investment properties as well.So far, I've driven around the neighborhoods my in-laws would ideally purchase and jotted down the addresses of the homes that clearly need some TLC.