Thank you for posting video I guess they are about 10-12 weeks old now.
I would suggest keeping them strictly separately and
firstly, sex them properly, see link for clear pics how to do it here and if you are not sure you can take clear pics post here and we will help you,
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Sexing rabbit pictures!
Because they are still young, usually in petshops they sell 8-10 week old bunnies or say they are that age.
Lionhead looks a bit older (not because bigger but because humping other's head), I guess about 12 weeks. Babies start humping each other around that age, I can guess lionhead is a boy, boys become hormonal earlier than girls. The other can be either boy or girl, just younger, maybe 8 weeks and will start showing hormones in a few weeks time.
No matter boys or girls, you have to keep them separately all the time, no playtime together until they are both neutered (plus 2 months after that).
They can be bonded ONLY after they are both neutered so don't try now, because they can fight really badly damage each other, especially when one humps other's head he can bite his genitalia and it will be very bad, you will need emergency vet and all that, also they will remember the fight and even when they are neutered they can remember that and it will be very difficult or impossible to bond them together.
Please take it seriously, rabbits can fight and there will be blood, I have a rabbit with a large hole in his ear because he and his brother were bought together as babies but they became hormonal at 3,5 months and had a major fight after that mine has this horrible scar around his eye and hole in his ear, his brother has scars on his forehead and multiple scars on their backs as well. They are very friendly and cuddly now and were before became hormonal, and kids saw their fight and were horrified so parents had to get rid of one of the brothers.
There are many similar stories, I am not trying to scare you but just take it seriously and keep them separately, ideally so they cannot see or smell each other, otherwise they will be under stress.
If they are both boys they can be neutered at about 4 months. I am almost certain that lionhead is a boy, but you better check.