Okay Felix I can help ya on a couple of these
The Band Played Waltzing Mathilda is an Eric Bogle song it's part of a three song cycle about the ANZACS during the first world war who were sent off to fight. The Other Two being The Green Fields of France ( or Willie McBride) and All The Fine Young Men. Eric is a scot that moved out to Oz about 30 years ago and has written slews of wonderful songs. Mathilda is specifically about the landing by the ANZACS ( Australian New Zeland Army CorpS)at Suvla Bay and the shit kicking that they got there because of the piss poor support they got from the British military.
Johhny Has Gone for a Soldier/Johnny I hardly Knew Ya: these a versions of the same song about how during the Napoleonic wars it was usual for recruiters to go round rural villages and Sign up lads for a shilling. Once the Shilling was accepted they were in the Army: Many unscrupulous recruiting sergeants sometimes got them pissed first (drunk to our yankee friends)and then offer them the King's Shilling. Also there's a version called "The Recruiting Sergerant".
Phe! I feel all knowledgeable and stuff now...I'd better go and have a lie down for a bit.