It's amazing you've been able to trace your ancestry this far back! I've had a look through the church records
and was only able to find a Thomas Power baptised in 1660 in Dublin.
Before 1864 records were kept in the form of church and parish records; while some of these have regrettably been lost over the years, all the surviving records have been sorted into county-based genealogical centres
. Have you been in touch with the centre in Waterford yet by any chance?
I hope you will be able to connect with other people researching their Power roots here, and that some of our experts can shine a light on this as well.
Happy holidays! :)