https://www.reapermini.com/PowerPalette
I like to use this on reapers site sometimes - it lets you click on an area of your picture and it will determine the best colour match (in their range of course). Even if you don't have Reaper paints it can be useful to give you a general idea of what you're looking for.
For your use, using
GW paints, I would probably get the following:
Moot green, warpstone green, averland sunset (yellow base), flash gitz yellow, Rhinox hide, Kharne Red, Evil sunz scarlet, Zandri Dust (bone base), Ushabti bone
Essentially on the yellow areas, base coat with averland sunset, do a layer of moot green over the yellow, where you want the green to be. Highlight with 50/50 moot green/warpstone green. Do a final highlight with warpstone green - if that doesn't tie in enough at the end of your painting, you can also do a final highlight with the flash gitz yellow.
On the areas that remain yellow, mix flash gitz with the averland sunset and highlight up to end up with just flash gitz yellow as a final highlight.
basecoat the teeth with zandri dust, then mix some of the flash gitz into the ushabti and do a final highlight with that - alternatively if that's too stark a look for you, get some lahmian medium (or other glaze medium) and mix the flash gitz in with that, to glaze the yellow look over a zandri dust base, ushabti bone highlight. You could also get lamenter's yellow - a yellow glaze that
GW makes - and do that over your bone look, but I think making your own glaze may 'match' better, with the rest of the model.
The darker areas, I would basecoat rhinox hide, mixed in 50/50 with khorne red. Then highlight with something like 1/3 rhinox, 2/3 Khorne red (I mysefl would just add more khorne red into the previous mix). On your extreme areas, where for instance you'd see light, I would start highlighting with the Evil Sunz Scarlet mixed 50/50 with the Khorne red.
Anyway, just my two cents - there's lots of ways to go around doing this sort of thing, hopefully you will find what works best for you =D
Good luck and happy painting!