Hi jnjn,
Once you've applied for I-485, you are pretty much in Status. You can continue to work. That's perfectly Legal!
I Know many cases, who have not applied for EAD or H1B Extension, pending I-485 approval.
But meanwhile, you can also apply for EAD/Adv Parole and H1B Extension to be on the safer side.
I exactly did the same thing in the order, I-485, EAD/AP and H1B extension. No problems.
Hope this helps.