I have said this on more than one occasion "this is a long term project not something that will happen over night" keep in mind of had aquariums most of my life. Not salt its new and a bit scary, but i thought these forums were to encourage people to give it ago and learn. But then ive also learned people dont want to see people try something new, because they are scared of unknowen an failure. An the fact it might be bad for image. This is my rant over now.
I think you misunderstand, at least in my case. From my point of view I have no problem with you trying to keep one, as long as you have the resources and ability to finish the project. You have mentioned that this is a long term project, but what about the rest of the issues you will have. Do you have a plan for the chiller? Is there room and time to get the correct size aquarium? What about the funds to accomplish everything you need to keep an adult?
You don't have to answer these questions here on the forum but before you get started you had better have answered "YES" to all of them for yourself and be willing to not waiver until it is complete.
Again, I don't know you or your experiences, I have a few suggestions for you:
First, start a saltwater aquarium and keep it for 6 months or a year and see if it is something you are willing to do. You can start up a fish tank for a lot less money and get a feel for it, the longer you keep this first tank healthy and are happy with it the better for you final project.
Next, move to a coldwater tank with the chiller and coldwater animals to see the difference, there is a difference in the types of equipment and individual animals but the maintenance will be about the same.
Finally, once you have decided to make the financial commitment, start the build on the big tank at the same time you get the young fish. There are several reasons for this, first you will be caught off guard as to how fast these guys grow. Remember in captivity all of the energy they get from the food will go to growth, they don't have to hunt, avoid predators, or fight off rivals or disease, all of the things that take up calories from food in the wild will be used to grow. The other reason is the fish will live a lot longer then it should in a small tank. We as hobbyists tend to see our animals activity and health and we are happy with that while in reality the animal has outgrown the space and should be kept in something much bigger. If you have started the tank build and put up the money you will not be caught trying to make temporary fixes to any problems you may have as he grows.
If you are here to learn, then use the information to make an informed decision, don't just assume everyone is just putting you down or discouraging you to try something that hasn't been done, a lot of people have kept wolf eels in aquariums but I would bet very few them got one before they had a place to put an adult.