I forgave a tenant of a certain circumstance, and I treat my contractor's crew to lunch when they are working on my property.In the future, show some professional courtesy and class by contacting a poster or BP directly if you think a post contains something "eerie" or nefarious. 

I am not the one making the payments, but it's still on my credit report.My limited income, combined with being a co-signer on the loan, results in a less-than-ideal DTI ratio.Under these circumstances, what type of loan or lender should I focus on?

They are two distinctly different things and that's what trips up most lower income housing investors. 

Knowing the seller's circumstances is very important as well.I also like to keep in mind my goal for investing in the property.

If you've lived in your town or city for 5 or 10 or 20 years, you will know things about it I can never know and thus you have a distinct advantage over me when it comes to investing - you know what a good price is, what a bad neighborhood is, what house looks good on paper but is underneath the airport flight path, and so on. 

The mortgage payment is already high and my life circumstances have changed, making the payment even more of a stretch (not impossible, but definitely above the recommended percentage of take home pay).I am considering selling the first property next year (which has about $200K in equity) to do a mortgage recast on the primary and get my payment to something more reasonable.

One thing you generally cannot do is charge their rent based on the fact that you MIGHT have rented it out sooner if not for these circumstances.

Circumstances like not holding annual meetings for corporations, not having corporate resolutions , commingling funds, taking money out of the corporation personally without that withdrawal being either a salary or dividend, etc.  

That basically leaves you with investors and buyers with let's say special circumstances.

Given these circumstances, I believe there may be grounds for a class action lawsuit against these companies, and their owners.