Here's my attempt. Sorry if it's a but rubbish.
Myself: of course.
The Barrow Wight: got to keep the landlord happy.
Gaffer Gamgee: To bring his amusing analogies and sayings.
The Saucepan man: Who knows? You may need a saucepan! (no offence Saucepan)
Morsul the Dark: Why not? You need someone Dark at a party!
Bilbo Baggins: We all need some good story telling.
Aragorn: So we have royalty on the guest list.
Seating plan:
The Gaffer and Bilbo sat across from each other, to share Hobbit talk.
Mr Wight at the head of the Table (keep the land lord happy, still)
Saucepan across from Morsul so they can throw things at each other for everyone's amusement.
Aragorn at the other head of the table. (hay, he's a King!)
Me, in the corner, the board looking one.