You can't pay debt with debt. They may be getting better interest rates on the bond market to refinance their existing loans but total liabilities are going up, not down.
Sure you can. That's the exact definition of "refinancing".
You may be paying off the note and it shows up as a different line item on the balance sheet, but it's not paying the debt.
There are a lot of reasons why moving it to a different line item might be advantageous...
I think I'm going to need a scanning electron microscope to see the hair you're splitting.
This is new debt not stock. These are bonds @5.3% which is close to the rate SolarCity was raising money.