Potential AC bonus's Low enhancement total.
Base 10
Mithral Full plate 9
Dex 3
Shield of faith (cl 11) 3 deflection(cl 12)4 Deflection
Dodge Feat 1
Magic Vestment(cl 11) 2 Armor (cl 12)3 Armor
Barkskin (cl 11,domain 1x day) 4 Natural(CL12)5 Nat
32 buffed ac at 11 without a single magic item is possible w/2h weapon
36 Buffed ac with a Heavy shield 38 with a Tower
CL 12 adds +3 ac w 2/h 4 w shield
Combat expertise can add another +2 Dodge bonus(dodge stacks,remember that)
So...the maximum self-buffed AC a CL 12 cleric can obtain with out a single magic item is a whopping 44.
Extend spell/Dodge feats are probabally given's Combat expertise maybe
I'd watch for any kind of magic item creation feats on the character,those are big 6 gateway feats.
The monkey grip feat allows 1 handed use of a 2h weapon(-2 penalty to attack)Being the group has 3.5 background...i'd look specificlly for that feat.
High Fort Saves,High Will saves,Lower Reflex saves 3/4 BAB Almost as much ease to buff attack as AC.Death ward and Freedom of movement in the defensive mix as well.Spell resistance may be in effect.Divine favor +3 hit/damage,Divine Power +4 hit/damage,Righteous Might+4 str/con(+2 hit/dam)Weapon damage upped to 2d8.Greater magic weapon +3hit/damage.
Glaring weakness...Hand spells,Force spells,and...lack of buff time.