Refinancing and credit score

[Kunal Domakonda]

I'm planning to start my rental property investing with single family homes in about 2-3 months. I currently live in a house that I am thinking about refinancing from a 15-yr to 30-yr term, reducing my home mortgage payments ~$1,100/mo. I'm worried about hurting me and my wife's credit score too much. 

Since credit scoring models treat hard checks on our credit in 14-45 day chunks, is it a good idea to do the refinance on my home as well as pre-qualify for the rental property together so that our credit scores aren't affected too much??