that's why I-485 is caled...

...adjustment of status. You are in a gray area in terms of status -- as you clearly put, not an H/non-immigrant status any more but not YET on immigrant status either.

As a result, you need the "EAD" to be eligible to work in the U.S., and the "advanced parole" to be able to return tot he U.S. in case of any foreign travel.