Stella: For six adults with luggage you will need a nine passenger minivan so you will have enough room for the luggage. Assume that each person with have two pieces of luggage (including a carry-on) that mean 12 pieces of luggage. That WON'T fit in a 7 seater minivan. If you go to the EasyTourIreland.com website you can get a quote on a 9 seat VW Caravelle in either manual or automatic transmission. They are the only ones who have a fully inclusive rate with no deductible and it is a Hertz vehicle. Check that out.
As far as your suggested itinerary you are OK but Iif you can I would reverse the itinerary as you wish to include Dublin. If you have Dublin at the start of your itinerary you can overcome 'jet-lag' without a car in Dublin. Since there are six of you I would suggest you engage Finta Murray (corporatetransfers.ie) to meet you as you come out of Customs at Dublin Airport and transfer you directly to you hotel. He is very reasonable, professional and punctual. Stay at the Mont Clare Hotel (3 star) or the Davenport Hotel (4 Star) both at Merron Square. Use the Hop-O Hop-Off Dublin Sighsteeing Tour bus (irishcitytours.com) with a two day ticket. You'll maximize your sightseeing. Then when you leave Dublin use Fintan Murray again to take you to the Hertz location and then he will 'pilot' you out of Dublin to the N11 and you're on your way to County Wicklow, Glendalough and over the Wicklow Mountains to Kilkenny. Stay at Pembroke Hotel (4 star) or Laragh House B&B. Visit Kilkenny Castle.
On to Waterford for a visit to the House of Waterford Crystal then on to Kinsale. Stay here two nights. Actons Hotel (4 star), Friars Lodge Guesthouse or Ashgrove B&B. From this base you can ferry across to Cobh on the Passage West ferry and visit the Emigration Museum. You could return to Kinsale via Blarney and Blarney Castle. In Kinsale visit Charles Fort (with a resident ghost)
On to Bantry, Kenmare, 'short Ring of Kerry,' to Killarney. Stay here for two nights. Killarney Lodge Guesthouse, Earl's Court Hotel, Harp B&B. Tour the Killarney National Park via Jaunting Cart to Muckross House & Gardnes. Also visit Ross Castle.
Tour to Dingle. Scenic drive to Dingle Town. Continue arounf the Slea Head Drive for spectacular scenery. Visit the Basket island Center and the Gallorus Oratory (7th century). Stay in Dingle at Bambury's Guesthouse, Dingle benners Hotel, Dingle Heights B&B.
Tour from Dingle to Tralee and up to Tarbert. Visit the Flying Boat Musem at Foynes before crossing the Shannon by Ferry to Killimer in County Clare. Visit the Cliffs of Moher and stay in Doolin. Doolin Hotel, Atlantic Sunset B&B.
Tour through the Burren stop at Poulnabroune Dolmen (2500 year old) and Kinvara to Galway. Stop in the city and walk the pedestrianized streets. Stay in Salthill at Roncalli House B&B or drive another 7 minutes to the village of Barna and stay at the Twelve Hotel. Stay here 2 nights. Tour Connemara from here, beautiful scenery spectacular contrasts.
Tour form Galway via Gort and stop at Thorr Ballylee, W. B. Yeats Summer Home and Museum. Continue to Bunratty. Visit the Bunratty Folk Park. Stay at Gallows View B&B, The Courtyard Guesthouse or Bunratty Castle Hotel. Take in a banquet at 15th cnetury Bunratty Castle or the Traditional irish evening in the Corn Barn of the flk park. Both great! The Irish night is best for familes.
Drive to Shannon Airport (10 minutes0 turn in Hertz car and depart for home.
Hope that helps!