I've seen a few instances on the biggerpockets youtube channel where the comments were suggesting the data used in calculations wasn't accurate.

For instance, if you're in some of the well known markets that multi-family does very well in ( Boston, Columbus, Etc. ) , multifamily could be a great starting point for your investment business. 

For instance, if he paid $40,000 to buy a house and sold it for $80,000 with $10,000 down, he could keep $10,000 in reserve  and tap into it to hire attorney, file eviction case , remove defaulting buyer/tenant and continue paying off investor loan (if he used PML to buy that house) while looking for the next buyer to sell it.

Pros/Cons, contacts even maybe, for instance how do you even acquire a loan like this, or is it the same as hard money dealings.

Typically when you see "cash only" the agent doesn't believe the property can pass a home inspection which isn't relevant for construction loans in most instances and there are plenty of banks, hard money lenders etc. who offer construction financing on distressed buildings.

In this instance what I would do is get the deed in lieu from the borrower so you ahve the property again and get a note from them but have an attorney draft it to see if you can include a confession of judgment - meaning if they do not pay then you can get a quick judgment and possibly garnish wages.I would also have them put a small down payment as part of the note and only accept a check that way if you ever did garnish you have a copy of a check so you know where they bank.unfortunately you are right they can stop paying on the note and its unsecured so its a risk but out of all the options this is your best option.

However, there are instances where it may be beneficial to perform additional cost segregation studies.You could perform a second cost segregation study after you’ve made large improvements to the property.

For instance, cities like Chicago are known for landlord-tenant laws that skew heavily in favor of tenants, and that risk should be baked into your underwriting.What’s your take on balancing short-term cash flow with long-term equity growth?

It's almost impossible to get deductible amount on some instances and owners are paying out of pocket.

In rare instances we will let someone pay through Square or Stripe, with them paying the cc fee, but only in unusual cases, such as one time with a tenant who was traveling and didn't have a bank account to use with our online platform.