Meanwhile, in the 4 years in limbo massive redevelopment was occurring in the area, and we were offered an amount equal to our investment plus a reasonable profit by a developer.   

Tai lopez it appears has really costs Norada Capital immeasurable harm. 

For capital gains realized from fixed assets such as real property, only 50% of the capital gains will be taxable if the capital gains are reinvested in fixed assets such as real property during the year the sale occurred, the previous year, or within two years after the sale.

The investor loss incident being mentioned (flamingo las Vegas) is an event that has occurred in Q3 2020.

I’m aware of loss harvesting when it comes to stocks, bonds, etf’s, etc. but how can this occur with real estate?

It's simple, plentiful, cheap, and emissions are less harmful than a cow fart. 

Capex- how much capex is needed, and what happens if only xx% occurs?

For example, you may reduce the maintenance and capex to 5% and then discover turnover occurs more often than you had planned.

Positive cash flow occurs as a difference in payment between 30 yr mortgage for $80K owner financed sale and fixed 5 year payment on a $40K loan he takes to purchase the house. 5 years down the road he still has a Note and 25 years to collect the mortgage while he owns the property free and clear.

The good wholesalers will have experience, knowledge (provide accurate ARV estimates or at least close), integrity in putting together win-win transactions, and a list of actual real cash buyers ready to buy (or capital/ capital partners to close on the property themselves if they can't find a buyer), so that the seller isn't left in the lurch and harmed by having their property locked up by someone who doesn't actually have any buyers or a clue on how to sell the property, or any money to buy it.