Color Scheme: pick a third color

[Gabbi]

I'm assembling models for a new faction in Warmachine I'm going to start painting soonish in the future.

Faction in Convergence of Cyriss. Official paint scheme is silver with bronze/brass gears and light blue glowing parts.

https://www.google.com/search?q=convergence+of+cyriss

I find them too sci-fi for Warmachine, so I've decided for bronze/copper armor (with lots of patina) and rusty iron gears and mechanisms.

I'm still undecided on the color for glowing parts.
Looking at a color wheel, and picking an orange yellow for the copper and a green/blue for the patina, the "triangle" would point at a blueish purple, am I correct?
So I could do the glowing part in a bluish purple. But...

1) Am I correct with my color wheel assumptions?
Would picking an orange yellow for the bronze work? As the bronze is a metallic.

2) To make the color wheel three-colors scheme work, I should go quite heavy on patina, right? To have the green tint impact as much as the orange.

3) How can I achieve a purple glow effect?
I have no experience in OSL and I would gladly stay away from that.

[Gabbi]

Example of models and official color scheme: