[Legolas]

Just as you need a base ability score to take certain feats (ambidexterity - 15 dex, improved knockdown - 13 int, etc.), it's your base ability score which determines whether you can cast spells of a certain level. If you don't increase your WIS to a base of 19 over the course of the game, you'll never be able to access 9th level spells for example.
Of course, a starting WIS of 15 or 16 is still enough to allow you that by the time you need it.

Charisma is useful for your undead turning, but also affects the duration of some domain-bound abilities. 12 or 14 is fine, you can increase this further with spells and items if you need to.

Intelligence is a requirement for certain feats, if you intend to take those you'll need to raise it to 13 or 14. Otherwise it all depends on how many skillpoints you want.

You won't need a lot of Dex. 8 is enough if you use the Animal or War domain, otherwise stick with 12.

Strength is where you pile your spare points. You have magic bags and the (empowered) Bull's Strength spells, as well as items to up that sufficiently.

Constitution is more of a priority than strength, still, it's not of vital importance.


The top domains (unless you're specialising) are Air (damage spells), Animal (Cat's Grace, an early Truesight, stronger summons), Magic (again, offensive power), Trickery (for the invisibility) and War (for the stat boosts and stat boosting spells). Strength may be worth it in some cases too.
In addition, anything allowing Stoneskin or Energy Buffer is welcome.

Find Traps is a standard spell all clerics get, so you would have trouble solely with locks.

As to attacks of oppertunity... most encounters go something along the lines of
-spot enemy
-cast protective spells
-turn corner
-cast offensive spell
-cast offensive spell
-chop up the rest

You'll generally be doing very little casting in combat, as opposed to mages or sorcerers. It'll primarily be improved invisibility, greater sanctuary, harm or heal. The first two effectively stop the combat, letting you cast protective spells and healing magic without worry for more attacks of oppertunity. The third means the combat is soon over, and the fourth, well, it's no different from drinking a potion of Heal. In fact, the potion is probably safer and leaves you with more spell slots.