I've actually taken another glance at Jean-Francois Dutertre's note on the song on one of his excellent Ballades Francaises releases. He does confirm that the oldest versions of the songs have both incidents, and that the French versions tend to emphasize Renaud's return and the mother-daughter conversation. I already knew that English versions of Olaf from Orkney emphasized the meeting with the elf-lady, so this answered my question more or less. It seems the "George Collins" versions do represent an older form, which broke down into two separate ballads, (Clerk Colville and Lady Alice) in England
I'm still interested to know about the custom of using intestines as trophies...anyone have more info?