Inventor can open a Pro-E file (and Solidworks) and convert it to a base solid. Once that is done you can use the feature recognition tool on the part to convert them to parametric features. See this link to watch the feature recognition in action.
There are also some softwares out there that will do this en mass, but they tend to be pricey.
Also, if you know Wildfire inside and out, you'll probably always be more comfortable with it, but if most of your customers use Inventor, I'm certain that your experince with Wildfire will make Learning Inventor a breeze. Good luck either way with your new business.