Vermiculture

I have a worm condo I have been wanting to setup.
I've read up and have a bunch of the nessicary things now. And a good idea of the types of scraps and waste I can add and should avoid.

My main question is regarding the actual worms, aside from their general size, and or geography they originally came from. Is do types matter. And how many is enough..

Say I found a worm every now and then and kept adding them , would that be sufficient. Would different types of worms handle living together?. Or should I stick to what seems to be the most common for sale as red wigglers… And since I didn't really want to pay to ship worms and dirt; is there really any difference from going to a tackle shop or any one selling 'bait' worms and just adding them?