re: Tax responsibilities for a RSA

Most people are given an option to pay the taxes or net settle. "Net settle" meaning you'll lose some shares to cover the taxes when it vests.
You won't be responsible for the taxes till the vesting year.
The value will be at the stock price when it vests.
Dividends depend on how it's set up. I've seen it a couple of ways. Most likely you will owe on the year the dividends hit the account. Most of the time the dividends aren't that substantial.