First of all the merging into one album cannot be helped, the only option is to change the name of the album for example name I had the same trouble with the two Cabaret albums I own, but now one is called 'Cabaret: 1998 Broadway Revival' and the other is simply called 'Cabaret' If you don't wish to change the titles entirely you can do very minor differences and they seperate into two different albums for example you could have 'Beauty & the Beast' and 'Beauty and the Beast' or 'Martin Guerre' and 'martin guerre'
The only thing I could suggest with the full Les Mis album not going onto your iPod is that you have not selected all of your music to be synced onto your iPod, this can be fixed by selecting your iPod when it appears on the collumn in iTunes under devices, and then selecting the tab that says music and select all music to be synced to your iPod. Either that is the case or your full iTunes library cannot fit onto your iPod which cannot be helped.
Hope I can be of help x
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