Significant figures on banknotes:

My choice, personally are politically neutral figures who have made a contribution to modern Ireland.

It would also need to be a gender neutral series. 3 men, 3 women, but on the highest note however, possibly going against the secular trend and purely for artistic purposes St Brigid and St Patrick in parallel (jugate) portrait alongside each other (500). This is NOT issued, but the design 'shown' for future use purposes and kept in reserve in anticipation of inflation. Typically like most countries, its a boring, non divisive, conservative choice. One of the selections is still alive(Maureen O'Hara), but Sir Edmund Hillary was on the Kiwi 5 when it was issued. Its a cultural thing, most who go on currency tend to be dead a considerable while unless they are Royalty or Dictators.

Also, anyone who has appeared before, does not appear again. That rules out W.B Yeats (Series B 20) Jonathan Swift (Series B 10), James Joyce (Series C 10), Parnell (series C 100), Daniel O'Connell (Series C 20), and Douglas Hyde (Series C 50).

Religious figures are out.

Women: 5 Maeve Binchy (writer), 20 Maureen O'Hara (actress), 100 Veronia Guerin (journalist/activist)
Men: 10 Patrick Kavanagh (Poet), 50 Michael Cusack (founder of GAA) 200 Sean O Riada (Composer and musician)

Lady Lavery gets retained as both a Hologram foil and watermark, although now that the forgers have managed to replicate the hologram foil type features, I'd start looking at a plastic see through feature. I'd be against going for Australian style plastic. Colour wise....follow the basic colours used on the first (1928) series of Pounds, and stick with that. That was each alternate denomination alternated between warm and cool.

Size wise, I'd go slightly bigger than Euro. The fiver is too small to handle, looks undignified and puny.