hi I'm not sure what you mean by "open plan" but for the 5 units you've mapped if they are sharing a common wall, but next to each other and not on top what you have for the outlines is good, but for the tags I would use building=house + house=terraced per https://wiki.openstreetmap.org/wiki/Key:house

It looks like the unit number 4 is repeated in your mapping though.