I have two siamese cats and indeed they talk ALOT! This is normal and they are very attached to their people. I personally let them into my room at night (along with the rest of the gang) and we all sleep like charms. No talking, just alot of cuddling and warmth.
For the bathroom issue...how many litter boxes do you have? What type are they? Are they cleaned out after every 'clump'?
Also do rule out medical issues as this can be the culpret.
Good luck and don't get frustrated as things can change if you want them to.