I tend to see Beorn's animals handled by them walking
normal animal style, with perhaps trays, cups etc. taken fom
the backs of some by the mouths of others (easily handled
elegantly by sgi)- but with no talking. Thorin's bird mesenger
could be shown listening and then carry written messages
between the Iron Mountains and Erebor.
And, yes, it might be quite interesting to see Saruman's
struggle for self-control (perhaps even show the beginning
of his pipe-weed addiction
).