Do people there consider Electoral Wards valid locations? When searching for a location on a map, do they look for their electoral ward, or their townland/ settlement? In example, Spelga. Would you look for Spelga, or the locations within it :Hilltown, Ballymaghery, etc?
Electoral Wards have been mapped elsewhere in the UK, but I think the tagging is somewhat suspect: they are not really administrative divisions. They also tend to change rather frequently, say every 20-25 years, and when they do the changes can be drastic.
Most of the rest of your questions are probably better answered by people from Ireland as a whole (OSM communities are effectively based on their respective islands). There is a project to map all townlands in Ireland, not just because it is important for addressing and location in the Republic, but also because it is of significant interest to genealogists. IIRC County Carlow is complete, and the tagging is well agreed.
So I’d likely start with townlands rather than electoral wards.
I don’t know if you are likely to get much of a response on this channel: the forum has never been very popular with English-speaking OSMers. Other places to try are talk-ie and #osm-ie on IRC.