Think we'd prefer the permanents remain as additional weeklies, so as to still have the same amount of recoverable weeklies for late joiners to Nightwave.
Making the permanents recoverable would be a nice mid-way, but would mean less variety overall, imo.
glhf with whichever way you go, but I'd recommend revisiting if they're recoverable or additionals, as I think as it shipped this week on accident is neat for the less involved playerbase or late joiners.