Data replication question

Currently I backup data from my PC’s to a server on site and then the server copy gets backed up off site to a cloud service; this way I a good practice of having the Backup offsite as well.

Now that my parent’s have a MBL I am thinking that I can start replicating data to their unit and once all is working consistently, be able to drop the Paid subscription to the cloud service.

So which would be the best approach, using FTP or utilizing WD cloud connection to remote unit, keeping in mind I will want to automate the process.

Same question.

We need to replicate our NAS offsite. Can we buy another one and somehow have them talk to eachother, across the web, on different networks?