I don't think so but AAD B2B has a bulk invite feature, hopefully that works in combo with Power BI:
Just to clarify, it sounds like they do have to be in the Azure Active Directory for this to perform properly. ...is there anyway to bypass that option? (Managing the addition and removal of users to the Azure Directory seems like a lot of admin time)
Inviting personal emails won't work because Power BI doesn't integrate with AAD B2C, so I believe AAD B2B as pointed above is the only way.