I feel like based on the colour theory I know that for Lucifer, the colour blue might have been chosen because of its associations with not just the heavens, but also as a signifier of his entire personality shtick.
According to coloursexplained, the colour blue has many significant meanings across several countries, but mainly it has the effects of invoking emotions of TRUST, LOYALTY, AUTHORITY, and CALM - all things that Lucifer stands for as the avatar of pride and Diavolo's right hand, as well as one of the main peacekeepers for the Devildom as one of its seven rulers (though "calm" might not accurately describe how he tends to rule with force).
However, it can also convey emotional detatchment, depression, coldness, and loneliness in its negative standpoints - which again, suit Lucifer down to the ground (sorry) as his pride and grief at the fall and losing Lilith caused him to withdraw from showing any extreme emotional outbursts. Especially since he had a kid from one of them.
Also cyan is the colour between green and blue. Read that how you will.
Green for Satan may have been chosen due to its connotations with evil (think Malificent. Scar. Jafar. The Huns from Mulan. All of them had green auras, green lighting, green magic.) But in general, green is seen as a sign of GROWTH,RESTORATION, CALM -all things Satan is either achieving or aiming towards. It can also be a symbol of INEXPERIENCE.
But what I find most interesting is according to coloursexplained, since it is made by mixing BLUE and YELLOW, it inherits pieces of both head and heart (mammoncoughmammon) and tends not to act in haste. Satan tends to be calm and level headed among the brothers - something he's fought hard for over the millennia.
So I guess I can see why they chose green? Even though there are many aspects that on the surface appear to clash with him at the core (growth, peace, nourishing, etc).
As for orange as his secondary colour, it's made by combining red and yellow - a complete absence of blue. It also means DANGER, don't come near this thing, you'll get hurt. It also means INSINCERE, FAKE, putting on a show... but also TRANSFORMATION. Lord of Masks, indeed.
Furthermore the juxtaposition of both of these colours is an interesting choice - green, calming and soothing, and orange, bright and loud and brash - perhaps showing the ongoing war between Satan's core anger and his learned calm?
Then again I'm not an expert I did art in secondary school and that's about it. Although yes, it seems like the devs are making initial notes then tossing them over their shoulder at some points. I'm still salty at Beel's character arc in the beginning of season 1 being meaningless.