You didn't say WHEN you needed the songs by, but I trust I'm still in time...

Rosemary Sutcliff, in her famous historical novel "Eagle of the Ninth", has included a nice little marching song that could be sung to any number of tunes (probably plenty in this database!) From memory, the lyrics of the first verse go:

"Oh when I joined the Eagles
As it might be yesterday,
I kissed a girl at Clusium
Before I marched away...."

It could be sung to the tune of "I Left My Love a Letter (in the Holler of a Tree)" - just one more idea, and if you pick a popular melody the kids might even join you on the chorus... :)