There is a 90% chance it will cause damage in your family.

Properties in rent controlled areas tend to have stronger appreciation due to the housing shortage caused by rent control 

Getting the right tenant from the start who is properly screened, eliminates a huge percentage of the issues that cause self-management to fail.Once you have a well-vetted tenant, clear systems for rent collection and communicationand a reliable handyman for repairs, I think self-managing is very doable for in-state investors with four or fewer properties.

Simpler the better is probably the right answer for most people early on.From your experience, what’s the most common thing that actually causes problems at tax time for small landlords?

You'll likely have to get a new appraisal if you have not yet reached 80% LTV of the original purchase price.Also, having a junior lien may cause some issues.

After that, it is usually a qualitative analysis among few choices.Creating a model like this will cause you to spend far more time "perfecting" the arbitrary model than actually talking with your prospects to get to know them.

You listed a few things that is slowing you down or causing it harder to scale. 

@Megan Samar, You could take a distribution from your 401k but not advisable if it's going to cause taxes/penalties.

The non-renewal notice just prevents month-to-month, but the original cause (missed January) still stands.

Do you or your contractors have sufficient insurance to cover damages to resident property caused by the work?