I believe all you actually need to do is force the merchant in question to draw their weapon (or raise their fists), though killing them also works, or simply forcing them to kneel if they happen to be essential.

Its worked as hit for all merchants, but since they have relativly low health, most attacks with decent weapons might skill them

The Predator's Grace boots (link to UESP) possess an overpowered Muffle enchantment as well as a 1% Regenerate Stamina enchantment.

Firstly, the UESP states that self-enchanted Boots of Muffling, similar to the Predator's Grace, have a magnitude of 1.0, compared to vanilla enchanted Boots of Muffling (observe the Notes section). That seems weird; it makes more sense for the Predator's Grace to have the special 1.0 magnitude, and for everything else, including self-enchanted items, to have the same 0.5. Is the UESP accurate in this case?

Secondly, the Regenerate Stamina 1% section of the Predator's Grace just seems suspicious. Is it special in some way (looking at you, Ring of the Erudite Magicka Regeneration) or is it as pathetic as it appears to be?

Predator's Grace is one of the few preexisting items with 1.0 Muffle magnitude. The others are: the highest level tier of Nightingale boots (level 32+) and Ebony Mail.

All other boots, including the generic boots "of muffling" and unique boots like Shrouded and Cicero's all have the magnitude of 0.5

Custom enchanted Muffle has magnitude of 1 regardless of the enchanting skill level and perks. So if you find generic Muffle boots, it is better to disenchant them to learn the enchantment and then apply it on the boots you like 

1% stamina regeneration is just that. It may have been intended to be like the Vegetable Soup, +1 stamina regenerated while the boots are worn, but ended up being lackster 

Many thanks!

No problem 

There was a rune thread recently I believe by Relycs. I believe he deleted it himself, perhaps in part because of my comment in the thread where I discussed my own findings regarding runes. Which essentially amounted to, they can potentially produce two effects, but I was not able to determine a consistent means of making that happen, and so I dropped my testing.

I have a list of which buffs affect each of the two possible rune effects (one is a guaranteed 50 point damage, and the other is a possible 40 point damage). I can dig it up if you want it; it's on my laptop which I'm not writing from atm. But I wouldn't advise putting much stock into the numbers unless you're able to figure out a surefire means of making the 40 point effect proc.

I deleted it because what I wrote seemed to be wrong.

Eh heh... me again.

Mason's Kingslayer suggests that use of the Steed Stone can be valuable for stealth. I understand that it causes armor to be weightless, but beyond that, I'm just a little confused. Could I get a look at the mechanics behind the Steed Stone and how it saves Stealth perks?

According to the UESP, the weight of your armor factors in on the amount of noise you do when in stealth mode. As such, a weightless set makes so that it is easier to walk around in silence.