Hello friends!
I've had these for a while and always wanted to do them up (since I love the models for some reason), but never got the chance. Now I do, so here is the progress I've made so far.
Here's all of my materials. I didn't use everything here, but I wanted the option.
I built the Wraithknights first; one with sword/shield, one with Wraithcannons and the last is a Skathach with Deathshroud Cannons.
Next I laid out some air-drying clay on the bases and positioned the things how I wanted them. I also used a Small Cobblestone rolling pin from GreenStuffWorld for that effect. I also added bark nuggets to simulate boulders/other rocks.
Then I added some sand, aquarium gravel, and rocks.
Next I made a mini bridge out of balsa wood. I don't think this is the final one I used, but it gave me an idea of what to do.
I painted the whole base brown and the rocks and cobblestones grey. A quick drybrush of light grey was next.
Added some liquid skill (aka Agrax Earthshade)
Then the fun part. I just threw on a whole bunch of flowers and grass tufts. It was like gardening, but different!
Finished off with some weathering powder
I also had a bit of a time getting water in the stream. I managed to do it eventually, but it was kinda touch and go there for a while

I'll add a pic of it later on.
For the Wraithknights, I wanted something that would compliment the base with a certain aesthetic I was going for, so purple seemed the natural choice. Any gems are going to be a light but vibrant blue (think Caribbean sea).
I simply airbrushed the majority of the model with Alien Purple (Vallejo Game Air) and then started doing some edge highlights. So far, I have 3 codpieces completed, haha. Here they are!
You may notice a bit of a gash on the Skathach Wraithknights chest. I had a bit of a slip with the round file then thought it looked cool so added to it. Will probably do some burn marks or something neat eventually.
Anyway, that's it for now. I hope to add more in the coming days
If you have any questions about how I did a thing, I'd be happy to answer them!