Alright, so I leveled my character a bit, and there is a direct correlation between weapon skill, str, and attack.
To answer the first question of what has a bigger impact on melee dmg, str or attk, your attack rating is what you do for melee dmg, so the higher your attack, the stronger you hit for.
Weapon Skill determines your attack rating, and with every 2 str you add 1 to attack. So, if you have 50 str and your weapon skill is 100, your attack *should* be at 125. Adding in meal effects... 100 Weapon Skill, 50 +5 str, and + 22.9% attack from a Meat Mithkabob = 156 Attk.
Attack is figured based on the following really interesting formula... as far as I can tell at least..
(Weapon Skill + .5 * str) *(1 + %attack bonus) = Attack
Whoever said algebra is completly useless?... wait, I know..
"Stand firm in your refusal to remain conscious during algebra. In real life, I assure you, there is no such thing as algebra."
-Fran Lebowitz