Advice on fixing Primary Residence prior to starting RE Investing

[Lisa Brink]

Hi I purchased my primary residence in 2016. I needed an FHA loan. I am in the process of refinancing to go into a conventional loan prior to starting RE Investing. My questions are: In California can you purchase a second if you have an FHA? When you do an investment loan do you normally impound taxes and insurance? What is the formula for calculating if this refi is a good deal for me (ie, current loan 535K, value 710K but PMI is 400 per month. Current interest is 3.75 and proposed interest 4.5)? I tried using the calculators but became a bit lost as I want to continue to keep this as my primary. Thanks in advance for any feedback. I am super excited to get things going on my investment business.

Lisa