sharing power bi premium reports with external users

Hi,

if I am want to share a report/dashboard backed up by premium capacity (as I am using Power Bi premium) with external users (outside my organization) using normal sharing technique (share, email, send... not using azure B2B method) . will the power BI premium advantage (ability to share dashboard with free users) apply to them too ? or it is only applied for free people inside my organization.?

To summarize:

what would be the difference if I sharing a report and I am using power Bi premium with a  power Bi free external users and power Bi pro external users

another question, will they  be able to subscribe to the dashboard ...and we notified by mail if a change  happened in the data? 

Thnaks