8. "Do they have different personalities?"
Nope. They behave exactly the same. All of the time. Sorry, I couldn't help being sarcastic.
This area actually really fascinates me, because of course they have different personalities - one of my boys is a stubborn old fool who insists, absolutely insists, on climbing on the dining table and helping himself to the apples... whilst the other one has attached to his toy rabbit and carries him around by the ear. One loves strawberries, the other one won't touch them. I could carry on here for a while.
I haven't exactly carried out any scientific research on the matter, but from my limited 'unofficial-would-never-be-passed-off-as-research' research, I think it is suffice to say that twins, irrespective of whether they are identical or not, do definitely develop different personalities. But also, as much as any siblings do, due to them sharing their environment, their experiences of being 'parented', some of how they develop is similar.
Identical means genetically identical - it does not mean carbon copy - or at least last time I checked.