I think they skew towards her being, well, a cat, considering she's "five apples" tall. Apples ain't particularly big.
Kiki and Lala's parents.
According to the Hello Kitty wiki, Kiki and Lala were sent down to Earth by their parents so they could be the "brightest stars". Which brings the question: what happened to their parents? Did they just abandon their children? Are they dead?
It's implied that they're still alive. The backstory is that their parents spoiled them a li'l bit too much and so they were sent to Earth to learn how to be good or, rather, better behaved.
Where did Cafe Cinnamon's owner go?
What happened to the owner of Café Cinnamon? She disappeared after the Cinnamoroll movie. Did she leave Cinnamoroll and his friends to fend for themselves?
After she was rescued (presuming you're referring to "Miss Anna"), she's likely just offscreen in the Cafe's appearances or Cinnamorrol just branched off to start his own café.