Is working a Ethernet HDD including additional USB HDD(WD My Cloud?) in Ubuntu?

Current situation:
I have minimal installation of Ubuntu LTS currently 14.04, soon 16.04 too.
I have some exteal USB HDD (WD 2TB, Maxtor 0.5TB, ADATA 1TB). Now I thinking about central data storage accessible from Windows and Linux (in the best case in Android too).
I found WD MyCloud HDD I have not bought yer. It seems perfect, Etheet interface pro connection to router and USB (with a USB hub) for connection of old USB HDDs. But official support for Linux is missing.

I have already found:
http://www.huffingtonpost.com/dulio-...b_5121961.html
so I know that WD MyCloud could be accessible from lInux.

Questions:
1. Is it possible to access the old HDDs (any HDD, not specifically my ones) connected via USB to WD My Cloud in Ubuntu/Linux? Did you try anyone?
2. Is it possible to set up backup of WD My Cloud to exteal USB HDD connected to WD My Cloud automaticaly? At least to one of them?
[3. Is is possible set up and manage the HDD from linux (or should done only from Windows). There is a web interface but I didnt find any documentation for that. But it is optional, I can manage via Windows.]
4. Do you know any similar solution supported by Ubuntu like WD My Cloud (Etheet drive with USB and automatic backup to them [for reasonable price])?

I am newbie on this forum please consider if I made anything wrong (I appreciate any notes about that).
I am rather newbie in Linux, I like instruction for dummies.