Ok, I solved it. I had to delete all my DNS settings that previously existed and then reset them. Once I did this within milliseconds Cloudron started working.
To know the backup scope, you can sum up all the apps listed there + email data + box data. Then you would have to multiple that by the number of backups which are stored (eg. once every day for 1 week or so) This would be the maximum of storage required using the tarball method. For rsync, it would be much less since it would do incremental backups.