1. I think there's more, but hard to add :) almost done!
2. Actually no difference. But if they're used as an exclamation of surprise at the same situation, natives don't use "진실 / 진실로", "참 / 참으로", "실제 / 실제로". Kind of an awkward expression although hard to explain in logical :)
3. Also there's no difference with/without "-(으)로". But usually, being "without" is preferred, for some reason.