I don't see a problem with it... I'd say go for it.
Best of luck!
Thank you for the replies! @cellanne, no discussion on middle names yet, but I'm feeling Benjamin or something equally classic and strong.
Dash Simmons doesn't have the best flow, but it doesn't sound bad either. Dashiell Simmons pairs nicely and I think it is a great name. Since you and your husband both like Dashiell, I suggest keeping it as a top contender and see if any other names pop out to you. Congratulations on the upcoming birth of your son!
It works. :)
It works perfectly fine. Especially when you add a middle!