Originally Posted by you

So you mean both Brian setting up Ethan and Gale fucking like beast are the participle which closer to the title/headline use of the participle

Yes. Brian'Then may be a real title. It is difficult to tell from that blurb. But in either case, these two are equivalent in structure.

Originally Posted by you

They are both participle because they don't follow possessives but Can I make them the possessive form Brian's setting up Ethan and Gale's fucking like beast in the beginning?? as the same as
david disagree about micheal putting up the posters
david disagree about micheal's putting up the posters


Grammatically, you can do that. Stylistically, the possessive + gerund is not normally used for titles. The participle form is more about an action. The gerund form is more about a thing. The gerund is a noun.