EBJD have a lethal gene when u cross EB to EB. I tried this, all the fry died after free swimming.
Best way is to cross the EBs with normal JDs and the cross them back to each other or EBJD to JD/EB. I got there and the fry do survive. I think Andrew has done it as well, he got there before me:)
By crossing to FH may not work