Very interesting! I think the clock is one of her invisible friends, too....she might be aware enough about time of day to have guessed pretty well on your husband's bus ride (they certainly hear/understand more than we usually give them credit for).
The thing about grandma? Who knows?
My dd2.5 is often making up stories about things she sees or has in her hands, balloons, toys. Or the black bear that dh 'saw in the trash' that is often 'going to get her' in order to start a tickle fest.
She is a bit of a fibber already. Uses the word 'secret' correctly, which was a little shocking to me, and loves to switch identities and object names.
I think Kriston's take sounds about right. I am thinking you and I will have our hands *very* full in another 10 years - lol!