Yes. Try the site at the link below for more details. There would be other private services too.
Dublin Bus was created in 1987.
Not directly. You would get a bus to Dublin from Kilkenny and then get another bus, or the train to Balbriggan.
You could fly. You could get a bus to Limerick and from there get a bus or train to Dublin. You could drive.
There are lots of bus services from Dublin Airport to the city centre.
What you would do is get to the Europa Bus Centre, the main bus station in Belfast. From there you can a bus every hour, on the hour to Dublin. Just check that it does stop off at Dublin Airport, as some of them may not do.
Get Bus eireann "Bus Number 13" to Limerick which connects with 2nd "Bus Number 12" to Dublin.
there is no direct rail service from Dublin to Tipperary town. Buses travel from the central bus station in Dublin (called Busaras) see buseireann.ie for details
taxi or bus to Limerick and then train to Dublin - about 2.5 hours
rail, bus or air
Try the Dublin Bus website below. The route number is 115.
Yes. The No 16 bus goes from the airport to city center. Use the Dublin Bus route planner to take you from the airport to stop no. 270, and you can see the entire route with every stop. You can also take the Airlink bus; an express bus, also run by Dublin Bus. Fares are higher, but it is quicker. Finally, there's Aircoach. They have a regular (every 10 minutes or so) service to city centre for €7.
Yes, you can get buses from Dublin Airport to Belfast.