I'm writing a short piece for an OU English Language course. I'm looking at the nuts and bolts of the English language as it relates to a particular area, specifically public arts such as

Yarn bombing
Knit Graffiti
Art Terrorist
Flash Mobbing
Guerrilla art
Guerrilla gardening
Graffiti bombing

Are these neologisms? They are not compound words but is there a linguistic term that applies to the word pairing?
Given that all these coined phrases concern public art is there a way of linguistically expressing the group?

Can any of you bright sparks think of any other linguistic angles that might be applied to such a topic? They are all new phrases so don't appear in the OED.

Thanks

Mark Thompson