Ferret collars are not necessary, but with a bell they are useful when out of their cage to locate them. If you use collars make sure it is a breakaway collar like used on cats. They can go places it could easily get caught on. Sometimes it hard to keep one on a ferret, you need to have it at the right length so as not to choke them, but where it won't slip off.
No.
Choke collars are for hunting dogs & working dogs. Those dogs need those collars to behaive.
For five ferrets, the largest cage you can afford as ferrets need room to move and exercise. Ferrets also need plenty of supervised time out of the cage for their health and welfare See related question and answer below for more information
Ferrets would need webbed feet to become semi-aquatic like the mink
Ferrets are nocturnal and they normally sleep 15-20 hours a day. Ferrets need daily activities outside their cage of about 4 hours
There are numerous dangers to ferrets, You have to ferret proof their environment, ferrets need to be handle by a responsible person (no small kids), ferrets need a special diet, they are carnivores (meat eaters) and cannot digest fruits or vegetables. Ferrets can be prone to illness and disease if not taken care of properly. They could be perceived as prey by some dog breeds.
Ferrets do no need their anal sacs removed, it is considered mutilation.
No, ferrets cannot live in a plastic storage container, aquariums, etc. Ferrets need a large wire cage (cages made specifically for ferrets) with plenty of ventilation. Ferrets cannot be caged continuously and for their health, need several hours out of their cage daily.
What makes dogs different from ferrets - everything is different between dogs and ferrets. Ferrets are not anything like dogs, there would be too much to list here. You need to read and learn about what a ferret is.
Ferrets are legal, but depending on which city you live in, you may need a licence, check animallaw.com for details.
Yes, Ferrets need canine distemper shots, only one vaccine is approved for ferrets. Canine distemper is fatal in ferrets (they die a horrible death) and is an airborne disease, being easily transmitted or brought in on your shoes or clothing.
They Like to bite!