Big Tim, Hugh had a wide knowledge of Irish songs and Scottish Gaelic songs. He was/is a staunch Socialist, Catholic and Scottish Republican. The first Rebel Ceilidh Song Book was printed in 1951 with Foggy Dew collected from Hugh's version who knew about the Easter Rising and Father P O'Neill's contribution. The vision of McAlpine's 'gang' as soldiers is, I think , explained in Dominic's comparison with/use of the two other songs mentioned. I think 'fusiliers' is a quaint term tying up modern gangers with soldiers. Dominic could have got the word from anywhere but you may be correct when you say Dublin Fusiliers.