I don't think the Blueshirts are considered properly fascist by historians, BCF. Fianna Fáil would be more populist if that's a fascist trait. And they have the tagline The Republican Party. Fine Gael have traditionally been in coalitions with Labour. Fianna Fáil were in with the Progressive Democrats who were much more right wing.
Fascism in Ireland was peculiar. It was hyper religious (RC) for starters and very much opposed to the Godless Commies as a primary motivation. The Spanish Civil War was its ideal confrontation and a contingent went off to fight for Franco, while the IRA sent a group to fight against him.
There was a street brawler element though, and a febrile atmosphere in the wake of the Civil War that made for tense conditions in the early 1930s when Ireland had two General Elections in a row, in 1932 and 1933. Cumann na nGaedheal played a Red Scare card in 1932, comparing DeValera to Stalin. There was also an attempt to shut down the Fianna Fail mouthpiece, the Irish Press, during the 1932 election campaign.
The Progressive Democrats were the Desmond O'Malley wing of Fianna Fail plus some defectors from Fine Gael. They had liberal views on social issues which they combined with conservative economic policies. While the rebels held strong convictions on Irish economic policy in the 1980s, the former FFers also hated Charles Haughey with a visceral hatred (the hatred was mutual) and it's hard to say how much of a part this feeling played in the creation of the (small) breakaway party. They all managed to pull together, more or less, in coalition, though it was always a bumpy ride.
Michael McDowell, who ultimately became leader of the Progressive Democrats, is a grandson of Eoin McNeill (prominent in early 20th century Irish history), so had a family legacy in politics (not unusual in Ireland). He was possibly the most knee jerk right winger of the PDs on many issues.
en.wikipedia.org/wiki/Michael_McDowell_(politician).
The 80s were a watershed decade in Irish politics, with shifting identities among all the major parties, and the generation born in the 60s and brought up with TV, foreign travel, less inclination to identify as practicing members of a religious congregation, and way more third level education than previous generations had access to beginning to make their presence felt in the voting booth. All parties responded to changing demographics, but the transformation of FG into a modern socially liberal party has been quite a spectacular example of holding a finger to the wind.
Irish political parties are virtually all right of centre, and when you strip away original identities forged around the Treaty negotiations and the Civil War there is little to choose among them from the pov of economic policy. FF tends to be populist and a bit on the spendy side (but again, depends how the wind blows), and FG tends to identify more with austerity (this is FG's achilles heel right now). FF tends to attract more socially conservative voters. FG has positioned itself as more liberal from a social policy pov but before the late 70s (under Garret Fitzgerald) FG and FF were both socially conservative parties. By comparison with the rest of Europe, extremely conservative. Labour have lost votes to Sinn Fein in recent decades, as Labour became identified as a party of champagne socialists out of touch with the needs of ordinary people. FF claims the Republican mantle but obv has come under some pressure since SF began operating as community organisers and ultimately contesting local elections and then general elections. SF encroaches on traditional Labour and FF voters.
No party really fits any specific niche. All are constantly evolving. There is nothing comparable to the (former?) blue vs red rosette of English politics.