Looking at the features, most of them plus many not listed are available in FreeFileSync, which is open source http://freefilesync.sourceforge.net/

Could you be more specific by what you mean by "not discoverable"? What service are you not able to use?

You'd be able to recover the file with incremental backups. A proper backup doesn't delete files just because they were deleted at the source. It uses file versioning to keep old versions of files. This, of course, does mean it will need more space, but has the advantage of allowing you to recover the file from…

First, I'd recommend doing constant incremental backups instead of a weekly backup. If your weekly backup is a weekly full backup, definitely change. Full backups of 3 TB of data would make me shoot myself.

I'd suggest something like ispy http://www.ispyconnect.com/ or zoneminder http://www.zoneminder.com/ on the backend. I, however, have never found a satisfactory wireless IP camera, so cannot help you on that end. Looking through some reviews of known supported cameras and…