Yes, this ^

The weight of the armor definitely plays into calculations - figured that out trying to sneak in heavy armor at level 1  That said, 1 point Muffle should eliminate that as well so you can just custom enchant some boots with Muffle and choose another stone.

Just a warning there are a number of mods that alter the Steed Stone many of them change what it does in such a way as it won't affect sneak.  Perkus Maximus, and Skyre are two of the ones guilty of this I know of off hand.  

How much hp does a Whiterun Guard have? (Lvl 50)

Any armor combos that match this?

look like Dragon and Chitin together.

Dragon plate armor (or the light version, which is darker but doesn't match with heavy armor perks): http://vignette3.wikia.nocookie.net/elderscrolls/images/e/e2/DragonplateArmor.png/revision/latest?cb=20131212015855
Imperial helmet (closed): http://vignette2.wikia.nocookie.net/elderscrolls/images/c/c6/Imperial_Helmet_Closed.png/revision/latest?cb=20120612172710

It's specifically when the merchant turns hostile, or dies.  If you're hitting someone like a college teacher, it may take a few punches before they'll stop warning and get to blasting.  That's when their inventory will reset.

I don't even know what you mean about radiant quest givers.

I read somewhere that bashing with an unenchanted staff while a weapon is equipped in the right hand deals the right hand weapon's damage.  Anyone know if that's actually true?

Yes and no. There are 2 different 'bash'-attacks while doing this. One beeing a standard bash, delivering the weapons damage + enchantments. The other one is a staggering bash that doesn't seem to trigger enchantments. This one, however, doesn't trigger more than 1/4 of the times.
Holding block will trigger the quick reflexes perk, if taken and you're attacked with a powerattack..
There's a build using this technique: http://tamrielvault.com/group/character-building/forum/topics/event...

So about 75% of the time, it uses the right hand damage and enchant, but the other 25% is the usual staggering hit that deals standard bashing damage?