Way of the Hundred Fists consists of 3 attacks, which appear to be 1 hit, 5 fast hits, than 1 hit again.

The 5 fast hits counts as one hit for any on-hit effect.

For example, if you have 0 spirit and use the full Way of the Hundred Fists combo, you will have 18 spirit since it gives you 6 spirit per attack.

I also tested this with on-hit effects by removing all equipment except a weapon with an amethyst in it (which steals life on hit), and found that during the course of a combo, I'd only heal 3 times.

As for your other question about the Hands of Lightning rune, it appears you are getting 3 extra attacks with no damage decrease per attack. I played around with it a bit, and although the damage per hit fluctuated a bit, it seemed to average the same per hit both with and without the rune.

The three attacks each seem to do 1/3 of 140% weapon damage each, so your 5-hit combo is around 9.3% weapon damage per hit, which results in an extra 3 hits giving you another 28% damage.

Just about the only thing you can do to speed up the skill switching process is to right click on the skill you'd like to change. By doing this you'll jump directly to the skill selection for that key, bypassing one page of the menus you'd normally click through.

This is the only way to speed up the process of changing skills. There is no other way to automate or hotkey skill selection in Diablo 3. It must be done through this menu.

Any 'out of the box solution' would require, at a minimum, the use of some form of third party macro or automation software, a clear violation of Diablo III's Terms of Use. While such violations are not always detectable or acted on, the possibility of action against your account and revocation of your license to play would give me extreme pause in considering any other solution.