Buying 2nd Property- Who should be primary applicant on mortgage?

[Account Closed]

My wife and I are about to purchase a new property and I am looking for advice on how to apply in order to secure the best interest rate possible.

Currently, we live in a house that is just under my name- I have not added her to this house because I had received advice that the purchase of a second home will result in a higher interest rate.

We will apply for the mortgage together, however is there any advantage to putting her as the primary applicant as a "first time home-buyer?"  Both of us have good income, good credit (780+) and we have a down payment of 20%.  

Additionally, we will rent out our current property- can expected rental income be factored in to offset housing ratio?  Or would a signed rental lease be enough for a lender to consider?

Down the road, our hope would be to set up an LLC once we have accrued several rental properties, but I do not think it would be beneficial at this time.