Ok....i've kept loads of different lionfish species and they really need the same conditions.
Firstly, they are as hard as nails and will tolerate poor water conditions....although you should only keep them in the best conditions.
They grow big....up to 12" in captivity.
They will eat ANYTHING they can fit in their mouth. If you thing a lionfish will swallow a 3" fish, there's a fair chance it will swallow a 5" fish....their mouths are huge !!!
Their dorsal spines are poisonous and can kill humans...although this is rare. If you get stung, you should apply as much hot water as you can take.
You should be able to wean the fish onto dead food....whole whitebait or any marine frozen fish. They are bulk feeders so feed them once every two or three days.
Generally, lionfish are very peaceful although i have known them to fall out with the occasional triggerfish especially at meal times. Other than that, large angels, tangs, groupers etc will make excellent tank mates.
Good luck