First. excellent job naming your objects in the outliner. Gold star!
If you want blade1 to have a separate material, in the material tab, next to the material name there will be a ‘4’, that means there are 4 objects all sharing this one material. If you click that 4, it will be made ‘single user’ or only that object will have that material and the material name will have .001 appended to it and you can change the nodes without affecting the others.
You could increase the thickness on the solidify modifier, although it’s about correct. You just need some children particles. In the hair system, toward the bottom there’s a section called children. Enable interpolated, 10 children is about right for this scene. So change render to 10 (not 100!) You have the system completely disabled from viewport, which is fine, so it really doesn’t matter much what you set that to.
The scene looks pretty good. I took the sun plane, scaled it 1.5, moved it right a little and angled it down maybe 30 degrees. Both hair systems on the dog, in the children, I added .05 random to kink the hairs a little.
10 interpolated children on the grass blades: