Lot's of nice work here
Suggestions;
I would personally recommend to drop the painted shoulder pads for James "The Black" Douglas, because the impression becomes on of a "super hero outfit", or least quite "gamey" to my eyes, rather than a more authentic medieval armour (perhaps I'm unaware of some actual noble practice, I admit).
Instead, I'd propose a plain mail á la your Wallace, or with plain steel choulder pads. So, less like this
but more like this [helmet aside]
Same principle with William Douglas I argue, while I find Andrew Moray look fair enough and Thomas Randolph looks decent with painted ones, unless coherency on the matter is preferred.