My advise would be determine who you are going to rent to. 

The latter would kill the deal, so I am curious to know how to determine this while I'm still in my review period.

OJT is typically not an option.Once you've determined an offer the lender is likely to accept, re-work your numbers and see if the deal is still worth pursuing.

Is there a particular way that you determining if they have equity?

As long as the relocation meets the two requirements above.Increase in Family Size - A borrower may be eligible for another house with an FHA-insured mortgage if the borrower provides satisfactory evidence thatThe has had in increase in legal dependents and the property now fails to meet the family’s needs; andThe loan-to-value (LTV) ratio on the current principal residence is equal to or less than 75% or is paid down to that amount, determined by comparing the outstanding mortgage balance to a current residential appraisal.Vacating a jointly-owned Property - A borrower may be eligible for another FHA-insured mortgage if the borrower is vacating (with no intent to return such as divorce, legal separation, etc...) the principal residence which will remain occupied by the existing co-borrower.

This market rent is determined by the appraiser.

Determine which size homes are most profitable to flip, then buy the ugliest home in the neighborhood that will still qualify for FHA financing.

Every type of loan has different requirements that will determine your maximum purchase price.

Once you have that income number in place you can then look at expenses and debt service on the property and determine if it makes any sense.

Well everyone, just read the last two paragraphs, the story is irrelevant to the question.If you buy a place for 200K and that is determined to be the market value and you find some sucker to pay 250K, you're into predatory dealing waters.