Does Crushing Blow and Deadly Strike count on Off Hand weapon?

For example if I am using a Death runeword on my off hand am I taking advantage of the 50% DS and 50% CB?

afaik, no, it does not count. Same for Claws on Assa.

Nope. Only passive effects like -enemy lightning resistance and such carry over.

And yeah, same for assassin claws. Not really much reason to dual wield claws besides +skill or WW though, attack is slower dual wielding than claw+shield and only main weapon counts on charge ups.

Dual claw sins would be more viable outside pvp if the +5 Frenzy on "Fury" didn't just apply to barbs. A Frenzy sin would be fun

I was messing around with different weapon combinations and I noticed that when I swapped weapons to cast battle orders and then swapped back my weapons were in the other hand than I started with. I had intentionally put Death in the primary (right hand) to take advantage of the CB/DS, but when I swapped to buff myself and then back my Grief was back in the primary hand (Right.) I only managed to notice this because I happened to make my death in a colossus sword which appears obviously different than a phase blade. Why does the game do this to you? Is it trying to put the weapon with the highest attack speed in the primary hand?

Please ignore that I made death in a colossus sword, the attack speed is awful, this was just for fun. I only noticed this effect because of the obvious differences in the weapon models. This has definitely been happening to me for a while but never noticed before because I was using two phase blades that look identical.

WSG is well noted, iirc. Pvp'ers talk about how to equip dual wield in an order to take advantage of better damage output, but that you have to reset it after a switch

For those using the extended stash mod it actually correctly calculates the CB/DS numbers on your extended character sheet and it only includes primary weapon stats.