On the jacket of the guy on the right the Gurren-dan logo.
That's a lot of Antispirals...
Y halo thar Attenborough.
Between the two girls on the right, Viral. And the tallest guy kinda looks like Kamina on a bad hair day to me, here's another shot of him.
From left to right: Attenborough again (between the girl covered by the chair and the guy with arms raised), Jorgan or Balinbow, Nia and Simon.
And, thought it might be just my impression again, the guy on the left in this picture gives me Leeron vibes (this screenshot comes from the second part of the episode)...
EDIT: Adding another couple, one was suggested by sagaranna in the comments:
Kamina's shades can be fit on anything, don't they?
Hidden between Panty and Stocking's hair, that seems to be Lagann. And the boy behind them seems to be wearing Simon's goggles.
That's what I found, if you got some more Easter eggs go ahead and post it.