Credit score - Heloc and investment properties

We are considering buying a business which will require a business loan and are still looking for duplexes which we would prefer to finance. We have substantial equity in our primary residence and thought we should secure a HELOC before we start taking on additional debt. My question is if there is a disadvantage to our securing the HELOC first and then the investor loans next. We have high credit scores and expect them to go down as we apply for loans. It may just be a wash. Thoughts? Thank you in advance.