with color in the face

Why not try to add pikemen into the Pictish roster? I know they historically never had any large scale pike formations, but they did use long spears that were about 2 time the size of people and had to be used with both hands rather than a shield.

On many Pictish stone carvings they appear with long hair and beards. So instead of using a lot of the welsh facial models I would instead try a mix of the the Gaelic but also Sudreyar faces with long hair and beards. The Sudreyar and Dyflin plaid arrangments are also great and would work well for 7th century picts. Just make sure they dont have Norse helmets. The helmets used for the Gaelic and Welsh factions would be perfect.

chariots? chariots were very common in pre roman briton, and hten when the romans invaded, the only place usign war chariots left was scotlan, where the picts were from.

body paint

i don't know if it's possible to add with the limitations of the assembly kit but a carnyx player would be a nice addition to units

I think Hengist and Horsa in their battles with the Picts, described them as short stocky and redhaired, think they also had tattoos IDK.

Maybe Berserker topless painted warriors, the type of units that made the Romans construct mighty walls and call the region beyond the walls (Antonine and Hadrian) "Hell" or demonland (Im making up these names but just to say that the Romans viewed Caledonia and Pictia as lang of mythology and super humans (negatively)