Will a co-sign to a loan increase the chance of pre-approval?

[Will Ducusin]

Me (and wife) are from Tennessee. My brother and his wife are from California.  WE are planning on buying our first single family rental property in Tn. I and my family will be the first "tenants" for the property. Our plan is for my brother, who earns way more than me, to co-sign on my loan application and we will split the mortgages while I'm paying rent on the property. 

Will having a co-signer increase our chance of approval? What strategies can you suggest?

[Trevor Alexander]

It will really only improve your chances of approval if your debt-to-income ratio is too high with just you and your wife's income. You already have good credit, and interest rates are determined by whoever has the lowest credit anyway. If you both make enough already for the SFR you want to buy, there's no need to have your brother co-sign. But if the goal is to split the mortgage payment, having him co-sign and have equal ownership rights makes sense.