I have an interesting trip coming up LHR-KEF-JFK--EWR-MBJ-LGW and have OW Sapphire and QR Gold status.

Will be travelling in a mix of W and J with IcelandAir (LHR and KEF, United (EWR), and Virgin (MBJ).

Question is what lounges will I be able to use at each departing airport if any?

My travelling partner doesn't have any FF status.

Grateful for any insight.