I have two questions if that is okay. I first made a line account and made my line play character (animal) and I kind of regretted it, however, at the time I didn't know how to delete it so I made another one using facebook. I heard it is easier to earn gems through the line account (with the adding and all) and wanted to switch but I have so many items that I adore on my facebook one. I was wondering if I could somehow convert facebook to a line account if that is possible?
As far as I know, you can't convert account types. (My suggestion to these asks is to possibly email support to see if they can make the switch for you, but as far as I know, once you've linked your account to something, you can't unlink/re-link it.)
I'm actually facebook-linked myself, and I don't think it's any harder to do invites than with a LINE account. You can invite any friends you have for the invite bonuses. (I have a 'fake' gaming facebook for just this sort of scenario.) If you linked to your real facebook account, you can probably still add a few random people as friends, invite them, and delete them when you're done.