ehm.
Bee-line (LH Group member) arrives to Luanda 7x weekly. Lufthansa mainline 3 or 4 times too.
Landing en-route at a listed diversion field should not be a concern. Any leads why it might be for a DLH crew?
Nailing an OEI VOR-DME NPA is a pass requirement on the EU checkrides, no different to elsewhere.
IFSD rate is a different kettle of fish, 100% that. Communicated on different channels than this one.