I am just asking if all users are allowed to add/remove a query/application to the dashboard(s).
I am also not sure if dashboards will be visible in the homeage or not.
Each dashboard has its own regular access rights, so unless its configured to allow "all users" to edit, that shouldn't be the case.
Each user can customize their own Shortcuts in the Links section on the left of the home page and in the little Flag menu at the top - these will be shown in addition to the global ones (that are set from <install>/settings/builtin/global/, I think).
Each user can also replace the "home dashboard" they will see with a custom one they can edit (or just see).
If you're writing code, there is this Developer dashboard: https://we.phorge.it/dashboard/view/2/
You can feel free to change anything about it, as it is incomplete
To make a Dashboard your homepage, click the Edit Menu link in the menu:
From there, add a new Menu Item of type Dashboard:
Find a Dashboard, add it to the menu, and make it the first item in the list. If I recall, that will make it your default homepage