minecraft and family sharing

I need some help please.

My one child used to have a samsung tablet, the other has an ipad.

We purchased minecraft for each child, one under google play for the samsung; one under the apple store for the ipad.

The child who had the samsung tablet now has an apple ipad (I gave her one of my old apple phones to use as an ipod and she purchased some music; so when we set up her new ipad we used the apple ID she had on my old phone so her music would transfer over)

We have family sharing but have run into a problem.

The family sharing is great in that both kids can use the same minecraft app.

However, they want to play like they did before where they could join each other's worlds and I think that they can't do this because they are both sharing the same game.

I think I need to buy minecraft for my daugther who went from the samsung to the ipad. when I try to purchase minecraft again, it says that it's already been purchased thru family sharing and won't let me buy it again .

I tried to remove that daugther from the family but can't do that because she is under 13.

I tried to add the same daugther to another family as I have a work phone and it's an apple so i have a separate apple ID for that phone and thought I could have her join my 'work' family there and remove her from the current (home) family she is- then we could buy minecraft for her separately.

I tried to invite her to my 'work' family via imessage. When my daughter clicks on it, it says that she can't join the (work) family because she is already a member of another family.

Help, I'm not sure what to do so that the kids can play on the same minecraft world together.. they keep asking me and I'm at a loss of what to do.

Thanks for your help.