If they aren't address numbers don't use addr:housenumber. If they are building numbers/codes use ref=*. If they are unit numbers you could use addr:unit but I think in this case they are probably just building numbers/codes which should be ref.

That said, if they are used for addressing then they should also be included in the addr:*=* tags https://wiki.openstreetmap.org/wiki/Key:addr:* but I'm not sure of where. You could also use addr:full for the full postal address.

Depends where you look for parking_space, for example https://www.openstreetmap.org/way/1058112357