For example, assuming a property ARV is 100K,  they will pay no more than 70 K for the property and cost of repairs , selling and costing costs included.

If the government  walks in one day and says "no more repatriation of profits off of your real estate to the 49% owner in the US, until we say further"  that is what will happen.  

I just fear that even with the proper test results showing the home has no more mold, any ARV based on a market analysis I come up with will be questionable because of the history.

If your numbers tell you that you need to pay no more than $10k below asking then that's your max bid. 

For example, if you can get $1,000 per month for a property, you want to pay no more than $100,000 for it (meaning your all-in costs including closing costs and rehab).

My "dream" is not to become a millionaire, but to live comfortably while working no more than part-time at the most.How long did it take you to build up a real estate portfolio sizable enough for you to "retire" on?

A good start to build on that $50,000 is to be a short term lender with terms of no more then 120 days and rate of 2 to 3% loan points with 10 to 12% interest rate.  

That Q pre approval is worth no more than the paper it's written on.  

There not making no more that's for sure.

Would definitely pay no more than 50k for a total gut rehab.