This change is not attested in any IE language, but I feel like it is plausible. Essentially, interconsonental laryngeals do not vocalize to i (as in Indo-Iranian) or to a (as everywhere else), but rather to their "underlying vowel" (e, o or a).
2. First Palatalization: kʷ gʷ gʷʰ -> ts dz dz /_[iey], except s_.
that said: why does the first palatalization only affect labiovelars? that seems a bit strange.