Personally I tanked Titan with full AK gear on pld and it went just fine(Used the crafted Kite shield and Garuda sword too), I did use food that boosted my vitality though. But, tanking titan is easy as all hell, it is the easiest role in that fight by far, you just stand in one place and take hits and use cooldowns before large hits that are perfectly predictable.

As for your bonus stats on paladin, yeah go all vit, there is no point in putting anything into the other stats, they won't be nearly as useful as vitality.

AK (Amdapor Keep), can be run no problem with AF, and should provide you with Hoplite gear wich will get you by np until you get your darklight gear. If you are concerned about your total HP pool the darklight accesories are pretty quick and easy to get(relatively low tomestone cost).