Answer 1: no, it is referenced in the Overview iView by application configuration that has the role/instance.
Answer 2: MSS uses launchpad but there isn't a launchpad role like with ESS. The main reason being that it works differently, you select the employee and then perform actions.
Answer 3: it isn't, the link between launchpads and PFCG roles is at the application level.
See Tips & Recommendations for customizing ESS Menu (WD ABAP) and also SAP KBA 1943809 to get started...