A great-looking mini! I must admit that one could really mistake it for a Salamanders marine, but since the new models of Alpha Legion marines also have scales on their armour, I think that the reptilian appearance fits with the fluff. A bit turquoise on the armour would have been nice, so that it can be distinguished from the Salamanders colourscheme, but it´s really a fantastic paintjob and a nice conversion.
Honestly, I think the idea of a big lizard even sucks for the Salamander Chapter.. I'm not trying to be the meany, but Space Marines are specialized, with organs implanted, psycho-treated bad ass humans, not lizards. Second reason for me to dislike your idea: Since when does the Alpha Legion have any link with lizards? their icon is a hydra, indeed, but they symbolize that by wearing it on their left shoulder, and on occasion some other places. If you would have converted the lizardhead into his shoulderpad, it would be AWESOME. now, even painting the powerfist so that it looks like a claw, you created some weird alien race in powerarmour.
on the paintjob: you've got skill, absolutely, but think of the Alpha Legion colours, green/blue, is not green, and a blue Ultramarine helmet under his foot. with drybrushes, blends or even washes it's very easy to create a green/blue colour, or you could use turquoise or something..
again, not to be mean, I'm just disappointed that noone seems to read fluff anymore.. and to make up with this words, a 7 should do on the paintjob I suppose..