Yes, they've past a G4 a few times.
Yulia screams a G5 in Show me love, Lena sings a very high harmony of a G5 in Malchik Gay, for a few examples. I have my keyboard right next to me so I can tell.
I agree with you that Lena has a very soft voice, which is why she is in the back a lot, though.
And I never said I don't like Yulia's yelling. I said people aren't supposed to scream too much in music, because it's not healthy for a persons voice to do the kind of screaming she did sometimes.
What I mean is, Yulia had a good powerful voice, but they shouldn't have made her try doing those really high notes.
Also, I still don't really hear any other pop singers that sound like Lena. Yes, they sing similar to her - there's only so few vocal types in the world. :| But I haven't heard anyone sound like her or Yulia.