Yes, there are many free resources out there, but books are one of many low-cost educational pieces that pretty much everyone agrees are worth the cost.Happy reading! 

All that matters is what you net after selling costs minus what you paid for it. . 

It would also lessen my out--of-pocket on either hard money costs or cash I spend, so I'd have more to work with to acquire more properties.

I personally don't think that will last if rates drop and people jump back in, so I'd say reinvest while prices are "low" right now. 

Given that many people have said the average price to build in California is $200 and above per square foot, I became worried.Do you think building a 2-bedroom, 1-bathroom home measuring 550 sqft is feasible at this cost?

You've listed what you can get in increased rent, but what would it cost you? 

Partner Driven financed the Finsbury Drive deal using its own capital, covering the $350,000 purchase price and $16,000 in renovation costs.

Option 1-sell it back to her ie tell her you want all of the money back within 72 hours PLUS all of the costs you incurred or will incur (eg mortgage penalty) as a result of her not moving or you will sue her. 

Assumable loans haven't been talked about much in recent years because interest rates were so low there was no point in going through the process.

If it's buy and hold make the landscaping low to zero maintenance to save on costs or having your tenants be responsible.