I see these as elemental combos, not inherited KG. Especially with the boil release, which is basically her altering the power and acidity of mist.
Something she gained through skill, not genes.
Not true. Hers are labeled nature transformation kekkei genkai. They are KG, but unlike dojutsu they branch from the elements. She didn't earn them via skill in my eyes. Or mokuton could be acquired via skill with earth and water jutsu.
Lava release and boil release, like mokuton isn't something one can learn or be taught. While Dust Release seems to be able to be passed down it's unsure how or by what means.
I'm sure having skill would allow you to use such techniques easier, but I don't think anyone can up and learn it regardless of being a god in fire and earth release. If your genes don't match up then you just can't do it. I go back to mokuton. Something that's not learned. It's just in the genes.
As for 2 kg (not Nature kg) it's never been shown to happen (correct and direct if I'm wrong) unless some kind of Orochimaru stuff went on.