Best practice sharing customer specific dashboards

I mean publishing and than create an app via powerBI service.

Yes you can create an app of Power Bi service with pro license and distribute that way. However I recommend sharing dashboard because you have a better control of the exact reports of the workspace that the customers can see.

Regards,

Can you explain that a bit more?

As you suggested the best way forward could be mapping within AD so externals can have access. With an app I'm able to let people find it in the internal 'app store'. With a dashboard I need to send them a link or email when I've done updates right? The app pushes updates as far as I've seen.

An additional questions:

-I've seen we can install a gateway for scheduled refreshed which seems to work fine for now. This is the best way to refresh data I suppose?

-With RLS we can manage roles. We can also use paramaters I've seen. However if I create a view, let's say "employees" and I want customer A to view al employees of organisation A and customer B for B. So the parameters are A and B in this case. What happens is that the full list of customers will be uploaded into powerbi right? So one little mistake in the RLS and people see eachothers data. So the other, much safer option, imo is to create views / query's per customer with the filter build-in. The con is that I need to query the database multiple times (for each customer) to upload the data each refresh. In RLS it's one upload and the rest of the load is within powerbi.

-When I change a report, e.g. a graph type or I delete an (old) graph it will not automatically update all affected dashboards. So the customer can still see the old graph (which won't get any data updates anymore).

-What is the easiest wat to provide (a selection of) the datafields to the customer so they can create their own extra graphs? 

I know it's a lot I'm trying to find out. That's also the reason I'm looking for a good direction to continue with.