In order to get the most competitive rate this way, you'll probably have to stay below 70 LTV and above a 1.3 ratio (that is why I was asking about if your sister would be paying rent).

Should I back out the deal and wait for another even with being in a fairly competitive market?

Are you getting quotes to keep it competitive? 

If buyers are financing with 10-20% down and hoping to secure a competitive property, I'll provide them an accurate competitive market analysis (CMA) and have my lender partner (or myself as a licensed NMLS mortgage broker) breakdown the differences in loan terms for an escalated at various price examples. 

Another issue is simply more competition.

The competition in your market will send a demo crew in and have the work done fast.  

High competition in some markets can squeeze profits.Rental Income Properties:Pros: Provides steady, passive income.

The market here is very strong and competitive- appreciation is at a very high rate at about 5% annually.

I love IGMS. very simple easy software to use and always improving. super competitive rates on it as well

You can offer to lend the seller money to stop the foreclosures. 7 or do a lease with an option to buy - making up the back payments that would be considered you advance lease payment.Always look at the property if you have intentions of bidding at the auction (this can be tricky because you need to do that with the owner's permission - do try to build a rapport with seller  - also look at the foreclosure suit to find out what the bank is looking for and if there is a second mortgage or other liens.At the court house steps when the auction take place you need to be well prepared with your certified funds but more importantly you need to know the fast sale value of the property - you don't want to pay retail.Get to know your competition - there will be professionals at the foreclosure auction looking to capture some serious equity.