Well Pictish culture was probably still lively by the 9th century but it was progressively merging with Dal Riadic gaelic culture. We have a picture of rupture but the reality was likely much more progressive as thought nowadays by most scholars.
However I would agree about most Kolba is saying.
I'm not a specialist of 9th century Wales. I got some books however that deal with Early Medieval history as a whole from 5th to 10th century as a whole and I occasionnaly read stuff about it.
I can say that your concepts don't fit the period at all - even if they are really excellent. Welsh would have dropped out Roman weaponry by the 9th century. Their weaponry would look similar to Anglo-Saxon, Norse or Irish weaponry and they may had an emphasis on guerrilla warfare.
Globally they would have less armor than their norse or saxon counterparts.
You could go for this unit tree for them:
Britons
1. Ardu ("levy") : basic levy with javelins or slings, made-up weapons such as cudgels, knives, handaxes, forks...
2. Aulue ("militia"): basic infantry unit with spear, cudgels, axes, javelins and light shields
2A. Milwr ("soldier"): better footman with better weaponry, some could have padded or leather armor but not all
2A-1. Bonheddwr ("hero"): better footman with better weaponry, light armor, a few with swords or longsax and some with helmets
2A-1a. Campwr "champion"): best footman with swords, some with spears, larger round shields, helmets, some with mail or scale
2A-2. Marchoc ("horseman"): light cavalry unit, with spears, javelins, axes, some with light armor
2A-1b. Teulu ("family", "guard"): bodyguard unit, with swords, helmets, larger shields, some with scale or mail or better organic armor.
3. Helwr ("hunter"): basic bowman unit, with cudgels, handaxes or knives as second weapon
3A. Saerthwr ("archer"): better archer, some with longbows, better weapons, a few with light protection
Saethwyr
3A-1: Arwreision: best archer ingame, quite versatile with padded or leather armor, good axes or langsaxes, some with light shields.
