Evaluating a set of records

I'm researching the Bartnett/Barnett family from Waterpark in Cork. The 1901 and 1911 census have just the one family listed as living there, and there's less than 100 people recorded as living in that townland. Given that, how much confidence would you place in identifying earlier records that mention both this surname and this specific townland?

For context, I know that my great great grandmother was born in Waterpark (based on the townland recorded in the 1926 census). Her father was a farmer named Daniel. I haven't been able to find a record of her birth but according to the census it would have been around early 1852.

There's a family living in Waterpark in 1901 and 1911, and I believe it's the family of my great great granduncle. But I'm purely basing this on the surname, townland and a marriage certificate that mentions the father is Daniel who was a farmer.

I've also found two death certificates for Bartnett's in the late 1800s who also lived in Waterpark, so I'm thinking they may be my great great great grandparents. But again, purely basing this on surname + townland.

There's no record of a Daniel Bartnett in the Griffith's Valuation, however I did find a Daniel Barnett living in Waterpark in 1852. In the absence of any other records, fair to say that this is the Daniel I'm looking for?

Also, trying to make sense of the map and the location of his house and land. Thought it was the highlighted 6A below, but notice now that it's an upper case A. I see that there is a 6B, for example, that isn't appearing on the list.