FreeBSD server(s) to backup multi-platform systems remotely

[Danny]

Good day to you all,

I would greatly appreciate any recommendations, related experiences,
and tips for the following goal:

On a monthly and manual basis - to take a snapshot of data from a
FreeBSD server and Windows server. Then compress and hopefully encrypt
the data and send it to a remote FreeBSD server through some form of
efficient and secure file transfer. Uncompressed a snapshot of all the
data may total over ~8GB.

On a nightly and automated basis - to take a snapshot of all new and
modified data from a FreeBSD server and Windows server. Then compress
and hopefully encrypt the data and send it to a remote FreeBSD server
through some form of efficient and secure file transfer. Uncompressed
the nightly data may total ~20MB.

Anytime (assuming the remote server IS available, of course)  - have
the ability to access the data and restore the data files to any
systems respective of what type it came from (Windows or BSD, etc).
And if a full restore was necessary, the data may total over 10GB.

Hardware and network-wise... here is what I was thinking:

FreeBSD & Windows Servers on the LAN
|
| LAN - firewalled
v
FreeBSD server where all the data would be collected and compressed 
v
|
| Internet - secure connection or transport of some type (SCP, SSH, VPN, etc.)
|
| Remote co-lo
v
FreeBSB server where all the data would be stored with at least RAID 1

Thank you!

...D