1. No, there isn't. As you mentioned, your actual to-hit chances depend on enemy stats, so the ability to see your theoretical base to-hit chances would be rather pointless.
2. Since enemy stats and encumbering equipment both decrease your to-hit chances, you will need a lot of Strength/Dexterity/Intelligence to reach the 95% to-hit chance cap, especially on higher difficulties. 19–24 points is not enough when fighting later enemies, at least not on Torment difficulty.
Quoting Slarty's min-maxing guide, "the 4-stat system means you can't have secondary attacks; they will be useless. Everyone has to pick melee or magic and stick with it." As such, you will not benefit much from increasing a warrior's Intelligence or a spell-caster's Dexterity. There's no need to place every available point into your primary offensive attributes, but any additional points are probably best spent increasing your Endurance.
3. Dual Wielding is not a useless skill, but both Blademaster and Lethal Blow are better for increasing a warrior's damage output. Since maximizing those two skills and Parry (and every warrior wants Parry) already consumes almost all of your available skill points, there won't be many points left over for Dual Wielding. Also, if you want to make a warrior as bulky as possible (which is a good idea on higher difficulties), you should maximize both Parry and Resistance. Doing this takes so many skill points that low-priority skills like Dual Wielding will have to be ignored.
4. As long as you place most of the available points into your primary offensive attributes, hitting enemies should not be much of an issue. I personally find even slightly sub-optimal to-hit chances very annoying, so my recommendation is to wear as heavy armor as you can while retaining the maximum to-hit chance.
All to-hit penalties stack, and the total penalty has no cap.
5. Sure Hand is not a good trait, since it does not increase your damage at all, unlike Ambidextrous and Dual Blade Mastery. Sure Hand only increases your to-hit chance by 5%, making it strictly worse than a single point of Strength, which does the same thing and also increases your damage. Maximizing to-hit chances is important, but you don't need Sure Hand to do that.
6. Many guides are written with min-maxers in mind. Since Melee Weapons and Pole Weapons are mediocre skills for characters that actually use those weapons and completely worthless skills for everyone else, you will optimally want to place as few skill points into those skills as possible. Thanks to equipment bonuses and paid training, buying 8 points of Melee Weapons (or Pole Weapons) with skill points is enough to maximize Hardiness (which is an excellent skill for everyone) and to reach Adrenaline Rush.
If you don't care about fully optimizing your party, increasing your Melee Weapons (or Pole Weapons) to level 15 with skill points alone is not terribly wasteful, but there are better ways to spend the extra 7 skill points.
7. This is really a matter of personal preference. I like to place 1 point into Mage Spells (or Priest Spells) and 1 point into either Melee Weapons or Hardiness after every level-up in the early game, until both Melee Weapons and Hardiness reach level 8. This strikes a nice balance between increasing damage and bulk and reaching Adrenaline Rush ASAP. Of course, you might occasionally want to place points into Tool Use or the Lore skills instead.
And yes, Adrenaline Rush is super good for spell-casters.