Is it doable - yes but you will need to go to a lender who probably uses their own funds vs. an instituational lender as they will not like 2nd position nor the low amount.

Quote from @Matt Pfefferlen: In a HOA foreclosure in California, does the homeowner get the excess funds after the 90 day redemption period is over or soon after the auction takes place?  

With no experience or funds to get going on this solo (currently a bartender), my thought was to join someone who is already doing it and learn along the way.

Private Money or Hard Money LendersIf traditional financing is a challenge, a private or hard money lender could fund the construction phase.

If I see a property on the MLS and I want to offer seller financing (or use creative financing strategies to fund the deal), do listing agents quickly disregard these offers?

Private financing would be an investor, investing their own capital and lending you the funds with their terms.

sell third house this time dump half the profit into SnP 500 index fund, other half builds fourth house... repeat until satisfied with stock portfolio, retire at 50option C) Aggressive model: sell house for $600k just keep carrying my primary mortgage which is $2900/month and dump the money into 2 properties and build 2 house at once that would each be worth $600k...?  

In this case, you can use Rental Income from the units that you will not be living in and that income can count to help you qualify.FHA rates are going to be lower than conventional for you almost always, but FHA does have a 1.75% funding fee. 

I've walked their properties in-person, and their build quality is good.

For my personal portfolio I use a modified spreadsheet amortization by VERTEX, available in Google Docs.