Any word on if any new dual and multiclassing options will be avalable in IWD2? Specifically will barbarians, monks and sorcerers be able to dual class?

I actually doubt that - the game developers are a little obsessed with maintaining the ballance - resulting in some kits beeing changed compared to BG-2.
Two classes that will certainly not able to be dual- or multiclassed are the bard and the paladin. As for the sorcerer and monk I expect the same.
I'm usure about the barbarian since he, though listed separately, is considered to be a fighter - so maybe there is an opportunity to dual or multiclass a barbarian - maybe as a barbarian-cleric or -druid (shaman counterpart).
Anyway, though it's a shame to put that on the end of a post, no one knows nothing definitive - yet.