From my research, there are certain deductions that lenders will allow self-employed individuals to "add back" to their income for lending qualification.

That being said, I plan to take the information and knowledge I gain here to seek a loan (pre-qualification) through another source. 

You need to ask the right questions, and listen to the answers.I recommend you include some of your key qualification criteria in the advertisement.

Lenders coming off the 2008-2009 financial crisis were still skittish about lending and were much more strict with their qualification requirements.

It seems the area in which hard money could help you is in the qualification process since there are fewer, "checks", to get the ball rolling.Some investors I talk to already have a favorite GC they decide to work with, so maybe, it would benefit you to find a GC that you'd like to work with so you can move faster in the earlier stages if you find yourself in a similar scenario.

Have specific standards for your minimum tenant qualifications. 

Scan/photocopy of the two most recent pay stubsAt landlord’s discretion, compensating factors such as an additional security deposit or co-signer (guarantor) may be required for qualification if Applicant fails to meet any one of the above requirements.

Hi - you should shop for other DSCR Lenders - this is the behavior of some more traditional or conservative DSCR Lenders that still require qualification based on LTR rents instead of STR. 

Should I turn down the job offer and stay at least until the end of the year with my self employed job to not affect my home loan qualifications?

I would just say that someone else had a higher qualification than they did.