BiDirectional Replicate question

Thanks for some assistance. It is frustrating that these devices are sold on the open market, but there is no formal presales.

Here's my questions: Still 3 unanswered.

1) Can two RN314s replicate to each other over the Internet? It would be a portion of the data, not all data. I assume there is a way to do this w/o creating an infinite loop of backup, but I can't find any presales documentation on it. YES.
2) I did find some doc that said that the first back has to be on the LAN. That is not practical as each is serving a different location. Can this be set up over a WAN/Internet? The backup data will be 2-4 TBs. UNANSWERED
3) Is there an additional charge or license required on one or both RN314s? NO, INCLUDED.
4) Can specific folders or content be replicated? PRESUMABLY
5) Is the replicated data on the remote RN314 accessible by file or total restore? UNANSWERED
6) Is there separate security? Can the local admin access the backed up content of the remote readynas? UNANSWERED

Is there a pre-sales 800 number or anywhere else to turn?