Thank you man! It's the part that I enjoy doing the most actually. Just added the weathering/bunny ears to the helmet tonight.
For the soft parts I am a huge fan of powders! They are so much easier to apply (I use makeup pads and brushes).
I first applied light coats of dirty down (black, brown, yellow in specific areas). I then use acrylic paints with a brush to accentuate lines/seams or darker spots as seen in the reference photos. For the acrylic paints I mostly used the dry-brushing technique.
The last step that I do is apply powders. I just dab the makeup pad to apply it and scrub it in a little bit, especially around the shins. Powder's aren't permanent, so it is very forgiving. One downside could be that they need reapplied over time, but they do leave a slight permanent stain.