I think the most suited for an adaptation amongst these would be Miss Saigon. Something about it jumps out as a film out of these three. Do we really need another My Fair Lady? I imagine a remake would be good but is it really necessary? Also, I don't see much of a selling point for it. Miss Saigon is a bit more modern. Les Miserables would obviously have a great selling point but it's such fragile material, and can be ruined so easily, with the right direction and production etc. it could definately work.
THEATRE 2016:
Grey Gardens; SwkPlayhouse, Cats; London Palladium, Into the Woods; Royal Exchange, Show Boat; Sheffield Crucible, Les Liaisons Dangereuses, Prsicilla Queen of the Desert; UK Tour, Narrative; RWCMD, Mojo; RWCMD, The Barber of Seville; WNO, Rabbit Hole; Hampstead, The Marriage of Figaro; WNO, Figaro Gets a Divorce; WNO, Tom: The Musical; UK Tour
Upcoming: Anything Can Happen; RWCMD, Cysgy'n Brys'ur, Long Day's Journey Into Night; Bristol Old Vic, Only the Brave, The Caretaker; The Old Vic, People Places and Things, Blue/Orange; Young Vic, Bernadette Peters, Carole King, Harry Potter and the Cursed Child Parts I & II