Bruce, dick, jason, cass, Tim, damian, Duke.
I thought about it for a long time and this just makes sense to me.
detailed version of httyd BATFAM au
What dragon each of them would have,
Bruce wayne, I belive he'd have a whispering death (mostly because we saw how it acted with the screaming death, her son) it's also silent so I makes sense, he also has a rumble horn to present his stubbornness. I guess a bat lookalike dragon would be most people's choice- but this is better in my opinion.
Dick grayson, i belive he'd have a storm cutter, due to the big brother energy It gave off, also the way the dragon moves is amolst athletic, so fitting for dick grayson.
Jason todd, now this is where it gets instresting. I belive due to the all blades, his death and what not, the dragons like most animals can sense him being a good soul (since he canonically went to heaven and was choosen by the all blades) I belive he accidentally keept getting more and more dragons until his place started to get infested with dragons, his place is basically like a dragons nest and he's the mother (like hiccups mother kind of) he of course doesn't own all of them, but these are the dragons I belive are closest to him to a point of them being his.
A nightfurry (due to it being death etc)
And a skrill, the night furry and skrill might not always get along so jason has to constantly repare stuff, along with a screaming death (that's why bruce having a whispering death makes sense) that lives underneath his place, at some point a lightfurry joins in, that's when jason has enough, because he doesn't want baby dragons to suddenly join in so he throws them out, but after a week of them following him he let them back in (yes he had to end up dealing with baby dragons later because of his choice) them there's a razor whip, it was a baby, so he had to raise it, and despite him being a male, the baby wasn't scared. It stuck to him, so jason let it stay, it's damians favorite, so jason tried to shove it off to him but the razor whip doesn't like anyone other than the man who raised him, aka jason, so jason learned to accept that the razor whip was going to stick around. Then there's a couple speed stingers, it's very helpful that they parelize the others when they get out of controle, what he doesn't like is when they parelize him. Then there's a deathsong that he had to fight due to it amolst killing his dragons, that ended up choosing to stay with him. These are the dragons closest to him. He only Flys the nightfurrys and razor whips, but somethimes let's the others fly with him, there are many more dragons that just stick at his place because his place turned into a dragon nest. They all are peaceful when at home (atleast most of the time) and jason doesn't have to take care of the feeding or cleaning cuz they do that for eachother.
and a sentinel, that keept trying to bring jason to the death island due to him..having died and shi, it keeps trying but the other dragons protect jason, so it just sits outside like a gargoyle.
It's rather usefull to have so many dragons be ready to protect jason, and having such a wide range to choose from. Also, Tim and damian are jealous that the dragons have chosen to like jason best. (Dick is just proud, and doesn't mind because his storm cutter is one of the oldest dragons, and ends up treating jasons dragons like younger siblings aswell, wich represent their characters too.)
Cass has a whispering death aswell, matching to bruce, but she also has a death gripper, that she knew when she was younger and only returned recently.
Tim and damian share a zippleback, to present them two being robin and at the same time fighting eachother like the twins and dragons themselves. Tho when tim turns to redrobin, he aquiers a gronkel (it being unconditionally loving despite tim messing up alot)
And later on damian aquiers a nadder and nightmare, that turned friends with the zippleback after it saved them, he choose to ride the zippleback alone without tim after tim left.
Duke, I belive he has night terrors trained, and that he has a fireworm (due to his lightpower)