You could view a sponsor's history and look at the returns shown on their track record, but without context it's meaningless. 

Double taxation would be when you have to pay US income tax and then also Canada income tax and you don't receive a credit for your US income taxes.

I worry about a renter with a good rental history being to cheap to put anything in but his grandmas avocado green range, cause it still "works".Not providing appliances in my area would also be a bad plan causing extended vacancies.

Generally, the properties that benefit the most from a cost segregation study are properties that are remodeled, expanded, purchased or constructed after 1987, the year in which the Investment Tax Credit was enacted.

Speak to everyone.You might investigate a wholesale line of credit if you are doing enough volume.

As mentioned seller credits are the best path as title insurance and taxes are pretty much fixed.

I have a few commercial loans that don't report to my personal credit. 

and how well my credit score will be?

It's a rare time in history for this.

I would give Prime Tracers a shot, they are pay as you go and you also get 100 free credits on sign up to try them out.