Oh wow Digo. I didn't know we knew eachother
Given the armor of the fallen, and sevral words from the other gems in the young-greg flashbacks, i think it's safe to say Rose knew what was what, after having many human lovers before Greg.
As for Steven's Gem, it's a popular theory that Rose might come back after he dies, though it is stated in a book somewhere that Rose completely removed her "program" and replaced it with Steven's. Who knows.