Sarah,
As people have already said, its difficult to know what is Irish and what isn't. My daughters have been dancing Irish STEP since toddlers (eldest now 19) under tuition of a lady who learned in the 1950s (and former All Ireland). Its changed a lot since then, though. What I can tell you is that the Ceilidh dances are danced by us parents using the figures only, without the fancy footwork. We just bounce around in time to the music. So I'd suggest you look at the step stuff only from the figures point of view. The dances you've mentioned are some the kids use.
SETS are a different animal. Depending on the capabilities of your audience (usually zero on St Pats) you may be able to teach them a few standard set moves (forward and back, round the house, turn the lady, etc) and then string various combinations together, perhaps in varying reel/jig/slide/ hornpipe rhythms.
But stop worrying about the feet! If you do see a expert couple, get THEM to demonstrate, and you'll have friends a future source.