I used Shelter for putting WhatsApp on the /e/phone of my partner. It works well.
(Also see Ohne mein WhatsApp geht nichts and WhatsApp einsperren (Shelter unter Android)).
I guess it can see your Sim card, as that is needed for connections.
I know that for WhatsApp: it cannot see your general contact list: you can make a separate contact list in Shelter (which is then only used for that WhatsApp install.)