Othni has more AC and HPs and mostly only spell foci, while Athlai has more melee foci but at reduced AC / HPs. I'd almost without a doubt go with the Othni for the Pal, as AC / HPs rule for tanks, especially plate ones. For the Ranger, I'd see if you need any of the melee foci from the Athlai, if not, I'd go with the Othni as well. Most of the melee foci can be gotten on ranged, and the other non-visible slots as well, if there is any still available.
Yther Ore.