My commercials loans are typically 25% down, 5.5-6.5% interest fixed for 5 years then adjusting with prime, 20 year amortization.I have been successful in using some owner financing to offset the 25% down, so for example 20% owner financing would allow me to purchase for 5% down effectively. 

Note that the rent and expenses numbers on the first tab are just made up, please adjust those to what they really are for your deal and it'll spit out your outputs for CoC on the first tab and IRR on the 2nd tab.  

Then you can adjust up or down accordingly.

Bought a condo in Las Vegas in February of 2005 with 5% down (FIRST and SECOND BROKEN RULE) on a 5/1 Adjustable Rate Mortgage after it had doubled in value in one year.

Talking to your aunt about LIBOR rate adjustments

You could even approach it with a deal-by-deal plan that way you can make adjustments as you each learn more and you're not stuck with a set of rules that doesn't work as you grow as investors.

I'm always adjusting my strategies, changing markets, etc...but, this time, I'm carrying an umbrella...just in case. 

Another lender suggested a 5 year adjustable at 7% and refinance when the rates are lower - what if the rates aren't lower in 5 years?

So, even if the properties declined 10-15% further, arm gets adjusted, the increase in mortgage payment per month should not be significant (I believe interest rate will stay low for a while.)

The repair estimate - I do my own repairs so it's slightly different but I have found that a 20% cushion for overages is good to start with - then adjust accordingly as you become better.Just my $0.02 - Best of luck