Read only access to some Fiori users

Hi experts,

We are currently building a custom Fiori app with edit/modify functionality for the fields.

However, there is a requirement that some users should only have Read access to this app.

We are quite unsure of the correct approach in the context of Fiori design principles.

Here are some options:

1) Create two separate apps: One is a Modify App that is has an edit button. One is a read-only Display App (only diff is the Edit button is not visible).

2) One app. Create a custom PFCG role which is assigned to users that should have Modify access - this role will determine the Edit button visibility.

3) Edit button is visible for all users. Upon saving, authorization check will determine if user has modify access - a message will be displayed if no edit authorization.

Which of the 3 options is correct with regards to Fiori princples, and why?

Thanks in advance!

Greg