Act 3 Merc questions

Ok, I have been casually playing D2 with my brother and some friends mostly lan parties, and most of us use act 3 cold mercs. Now, I would like to know is the damage that is shown directly related to that of the cold bolts?
I got a falcion equipped with 100 poision damage, is that converted to cold? No poision seems to show up in the monsters.
Also, is the attack speed of the weapon directly related to the cast rate of the cold bolt? It seems that when fanactism is equipped they cast faster but I cant really tell.
If it is directly related to weapon speed would a increased cast rate item also speed it up?
Any imput would be a great help, thanks!