Should be pretty easy, Make a dog companion or copy one already in game, switch its race to wolf but keep its voice as dog ( wolfs don't have dialog like dogs) or if you want it to have a human voice you could do that as well. I would make a copy of the wolf race (be sure under copy data on the race you make to set the morph race and armor race to wolf race) to use for your companion so you can set it to allow pc dialog and un-check cant open doors, that way it will follow you through doors and can talk, be sure to set its faction to current follower faction and set this to -1 and then add potential follower faction and leave it as is, this will give them follow dialog and commands ( as long as they have a voice that allows dialog, not all do). For the fire breath you could just add the dragon fire ability to it if you didn't want to edit the afflicted ability. pretty simple stuff really for a basic follower, i have made dragons ( still buggy) spriggans trolls lol its fun .
edit - i could actually whip a basic one up really fast to see how well it works and there are a few way i or you could go about it .
1 the fully custom way i described above, but for the wolf to have full follower dialog it will need a human voice or you would have to add your own dialog's. but if your lazy like me you could for example give it female even toned voice and follower faction and it will talk and have all follower commands.
2 create a " stray wolf " creature that uses the stray dog script, it will pretty much follow you everywhere once you interact with it, but these have no commands. (i think)
3 you could just straight edit one already in game, like Meeko or even the trained dogs sold in markath. With this method your would would live in meeko's shack and you can talk to him and have him follow you when ever you want and send him home if you and it would be a wolf with bog voice.
but like i said if you want it to have full NPC follower dialog like hold items go here, wait , follow etc it will need a voice that can use dialog's and add current follower faction to -1 and potential follower faction .