The 1st one really does look like a quad with the grooves on his head. The 2nd one looks like my baby P.alleni with his tiny claws but he's a darker smoother blue. In other words I don't know for sure and can't wait for someone knowledgeable to come along lol
I've got this picture I took the other day, it's not real clear although it shows the color. Mine looks.....more of a mottled light blue and the 2nd pic you posted-he/she looks more even and smooth. There's ways to tell by whether the plates (areola or something it's called) on their back are closed or open. A blue P.clarkii has them closed.
All crays antennas look long to me the bigger they get lol My quad's body is just under 7" and I swear his antenna are longer than that. So yea-I think the alleni has long ones but I think they all do