Question about procs on weapons

Can spells without weapon damage% activate procs on weapons, for example, can bloody pox activate Fang of Chton? If not, can constellations with wep% (like flame torrent) activate it?

How do procs on offhand behave? I remember reading somewhere that offhands are like armor, they don’t need wep% in a spell to activate, but shields are treated like weapons, and the attack has to come from the shield to activate procs? Is this still true?

I’m building a conjurer, and my weapon setup will be fang of chton and orb of the black flame. What can activate the procs on those items? Orb’s proc should activate on any spell, without wep%, and fang would need a spell/devotion with wep%, like flame torrent or chaos strike. Am I correct?

The procs activate off any non-dot damage.