Both would have a core selection of Outremer/Latin infantry/archers, possibly cavalry too [A generic 'outremer' knight + Strelac's Turcoman]. We could have a different texture for their units, though it would be minor alterations. I'll do some research into it, but it'd be the usual faire.
Both, probably, would have access to Templar and Hospitaller Units (Much like the Ghulams, we could have Mounted T/H Sergeants and T/H Knights.) Because the textures will be mostly the same for all of these, and so will the mesh, we can be a bit liberal with their roster. I would suggest:
1) T/H Knights
2) T/H Foot Sergeants (Spearmen)
3) T/H Foot Knights
4) *Optional* T/H Crossbowmen.
1-3 would be using the same mesh and very similar textures, with differences in helmet, weapon, and shield. Maybe there'd be a slight variation in the mesh for the knights, if it was historically shown.
4 Would use some other mesh/texture and isn't a really needed unit. This isn't really too much, because the Muslim Factions will get 3 Ghulams (Junior, Bow, heavy) along with 2 Turkomans (3 if they are Turkish).
I can't say there'd be any difference stat wise between the two. But we would basically be using the current Hospitaller/Templar texture, and just alter the helmets, so there isn't much work cut out for Alpha. We could maybe for gameplay make each cover a different field, as is done now in the KoJ Roster: Templar Knights and Foot Knights, Hospitaller Foot Spearmen and Knights. But what I figure is that T/H units are basically slightly superior to their secular counterparts, yet are rare enough (Recruitable for Crusaders only in castles which historically held them? Or in guildhalls?) that you cannot rely on them instead of your secular units.
Then both would have some special units:
Armenians (Simply use a few Armenian units. Not sure which)
Norman Knights - Best charge in the game, disciplined (Not highly), high moral, high close combat abilities.
You could feature 2 types of Norman Knights. One, with only heavy mail hauberk but much more colorful and noble looking than other knights, and another with scale and lamellar (As some have adopted), being a Knight whose closer to the Eastern Ghulam. I can't say that Normans should be a universal Crusader Unit, but the stereotypical norman look would be, in the Outremer Secular Knight.
Dismounted Norman Knights
[This hasn't been researched, is just creative idea regarding the impression gained that Antioch was Western and KoJ along with Tripoli more adopted from the locality than Antioch.]
"Saracenized Knight" - A Knight whose realized the value of less rather than more. Adopting the Arab style, they fight as lighter cavalry with a strong charge but less armor. [Basis is in seeing some artwork of Crusaders who had adopted Muslim styles, with a cloth wrapping on their helmet, or a colorful arabic-like lower garment]
"Saracenized Heavy Knight" - Possibly a Knight whose chosen to adopt the heavier armor of some of his Muslim Foes, with lamellar or scale added. [Basis is in concept art which showed lamellar used by Eastern Normans.]