If you collect the info for just this specific purpose (maybe something like "Facebook takes down pages all the time, please help me keep in touch with you by s

If you collect the info for just this specific purpose (maybe something like "Facebook takes down pages all the time, please help me keep in touch with you by subscribing to this email newsletter! I promise to use it only in the case that Facebook takes this page down or it becomes otherwise unmanaged by me") then I don't see why it would be complicated, just as long as it's something they intentionally do and you're clear about how you'll use the data.