Good Morning * Young Gr ma* D. ;) Is your little great Nephews name Corbin? :)) Sounds like our gr son, he is just as sneaky and quick! I have used Mr Clean eraser for Lipstick, magic marker, Ink pen's, Steam machine for Pepto on carpets & furniture.
You may want to get out the cleaning instruction booklet for your loveseat, dry erase may take it off the picture frame. May call a dry cleaner to check on the sheers.
One Mama usually writes with a not toxic, all natrual cleaner, ( sorry can't remember her name) that may work on it all.
Since you live in Mo, and we live in Ks, maybe our little guys will not meet and share sneaky tales & high Jinks ;)
Good Luck to ya D., hug the little guy he sounds like a keeper.
K. Nana of 5