The song "We're All Good Pals Together" was sung by soldiers of the British Empire during WW1, so it must predate 1918, however it makes an appearance in the 1937 film "The Show Goes On" as sung (and recorded) by Gracie Fields.
"Here we are again, Happy as can be,
All good pals and jolly good company.
Strolling 'round the town, Out upon a spree,
All good pals and jolly good company.
Never mind the weather, never mind the rain,
Now we're all together, whoop she goes again.
Lah-di-di-di-da, Lah-di-da-di-di.
All good pals and jolly good company."