This advice is worth about as much as it cost ya as I am no worm expert but I will offer up some thoughts shaped by my own interest and reading.

The nightcrawlers are deep dwellers residing in permanent vertical burrows, these need to be left undisturbed for their best benefit as this is like their house. Think about it that way and you wouldnt do too well if you had to rebuild your house every few weeks. They come up at night and bring down organic matter (OM) in a small area around their burrow. Seems I read somewhere that some even stay in contact with their burrow so the feeding range is the length of their body. I believe there are different nightcrawlers as far as cold hardiness (Canadian Nightcrawlers).

European Nightcrawlers (EH), these guys really arent even nightcrawlers. They are in the same family as red wigglers since they live in the upper ranges of the soil/litter. This is the worm I have and I find they do well in the soil and have wintered over here with our lows into the teens. I scattered them in different areas of the property including the lawn, garden, greenhouse and compost pile. I have found them in all of these areas, prior to releasing them we had no local worms and now any places that get some semi regular water and have OM litter they are reproducing and increasing in numbers.

Red wigglers (EF), these are nearly identical to the EH in appearance and habit. As I understand they are not quite as suited for outdoor release but then they live nearly everywhere showing up where animal manures accumulate so they apparently do live outdoors. They are quite well suited with the quick reproduction rates and mass social living preferences for container rearing indoors or even outdoors in temperate areas.

Both the EH and EF do not make permanent burrows so tossing their neighborhood from time to time is not a problem in fact it may even help them as it will aerate and fluff the medium they are living in.

Most important things for your own choices will be what you want the worms for and what you have to work with in providing a good environment for them to live in.

Does anyone have information on which of those species eat more, require warmer or cooler temperatures?