I'm pretty sure the house has always had a 1% house edge, and I'm almost certain there was never a 0% house edge.
Then I've clearly fogotton the name of the other site that used to offer a zero percent house edge (to attract people in at the start - maybe I'm mixing it up with a mining pool or soemthing)...
Anyway, yes the rakeback does affect the house edge, is that for every level or just certain ones (I think you have to get to a certain level to activate it but is it every level after that that you get a rakeback)?
Starting at Level 7 you get 1% of the 1% House Edge back on your wagered (0.0001% of wagered), this increases every time you level. For example, I'm Level 17, and I get 11% of the 1% House Edge back on my wagered.