I'm saying it's 25/75 per a private agreement and how my parents have set it up in their will as well but for all intents and purposes, could we treat this as a 50/50 arrangement at least when it comes time to sell under the same circumstance?)

@Landon Belk answers to your question will be different depending on many circumstances.

I am considering keeping my policy and not allowing co-signers/guarantors under any circumstances and just keep looking until I find a better tenant to meet my standards on their own.

Some smaller deals may even be financed with seller finance only or by assuming the existing loan on the property due to a number of circumstances.

In the right circumstance these can be very helpful.An improvement exchange has the QI taking title to the new property before you do. 

Best to talk to your CPA/EA who knows your exact facts and circumstances and can lay out all the options.

But look in the mirror and if you can say with a straight face that your intent was to hold for productive use and some outside circumstance is causing you to change your intent. 

I moved around shortly after that for work so out of circumstance, this house became my first rental property.

In what circumstances would you be stricter with the rules?

The absolute lowest income tax strategy isn't always the best for the taxpayer.Regardless of the path chosen, OP should definitely consult a pro who can examine facts and circumstances, as well as goals.