COM to Dingle

Both drives are quite doable in one day, especially if you break them up with stops along the way as you propose.
Liscannor to Kilkee only takes about an hour along one of the prettier coastal drives in Ireland. About the only things that might slow you down will be the chance of bad weather that day or encountering congestion on the N road.
The Cliff Walk at Kilkee is terrific and should take about an hour give or take.
Likewise the drive around the peninsular loop won't take too long depending on stops to take photos, etc.
Coming into Dingle from the direction of the Tarbert Ferry will allow you to drive over Conor Pass - a very pretty way to go on a sunny day. If the weather is inclement you might want to give it a miss and just come in via the N road to the east. The drive over the pass is great but not much fun if it's foggy or rainy - and it necks down to a single lane in places requiring an extra bit of caution.
Kenmare to Navan will be a long day but a pleasant one if you take a break along the way at the ROC.
You can preview your daily drives by using the street view feature on Google maps. Most here suggest adding about 30% to the estimated drive times shown on driving apps, especially when using the N roads which can be slow going.