The question is mostly a personal financial planning question and it depends on your preference and what balance of risk and access you'd like and would be comfortable with.

From there it is really just a matter of determining comps, cost to rehab a property, and your timeline.I have helped several investors flip their first home in Austin and learn how to do it effectively.

I would like to build several (2 - 6) "shipping container" type homes for either short, mid or long term rental.

Hi, pre foreclosure in all of its permutations, before the bank sends Notice of Default (NOD) or efter which is state even county dependant but often starts a 4 week clock till the trustee auction are the 2nd most difficult deal scenario and IMHO only experienced investors should bother, the 1st most difficult deal scenario are bidding at the court house steps on lord only knows what is being auctioned off sometimes even 2nd mortgages, you need to do so much home work to attempt to reduce your risk at the court house steps...Pre foreclosure no one talks about these issues, always about the nice sounding stuff like "motivated seller" get a good deal etc etc both are usually not the case.- 95% of folks in pre or post NOD want to stay in their house, keep their house inspite of them 100% will loose the house at the auction. 

@Emeka Okeke, while it can be debated, in my opinion, by far, one of the more simplistic ways to take action and learn the ropes of real estate investing, all while mitigating risk, is to house hack your first deal.

Congratulations on the duplex -My investor clients have acquired several multi-family investment properties locally in the market I operate in Northwest Indiana - Figure out your personal investment objective for the next 4 years and align yourself with the next property that make sense in this current market environment-

Several years prior to Covid I got my finances in order to start investing.

Looked on zillow for several weeks.

The risk of property damage or a lawsuit from a dog bite is too high. 

There are several options for skip tracing to find phone numbers and email addresses.