The following are merely logical guesses ...

STR - Strength. Affects how hard you hit in melee
INT - Intelligence. Affects spell learn rate for Mage spells, as well as effectiveness those spells
PIE - Piety. Affects spell learn rte for Priest spells, as well as effectiveness of those spells
VIT - Vitality. Affects your physical defense. Also affects how many HP you gain on a level-up.
AGI - Agility. Affects your Dodge rate
LUC - Luck. Affects everything to a slight degree

As for how to assign points, that depends both upon the class and your plans for the character's future. If you want your characters to advance to higher classes, you can either keep rolling for a 40 or a 47, or you can level the characters up in a base class with an eye towards changing class later. If you do the first, then simply assigning stats and alignment to get the class you want is the way to go. If you are going to do the latter, however, then assigning spare points to LUC or AGI or INT or PIE may make it easier to get the minimum stats for the advanced classes later on.