Do both ethernet + esata work together with usb-connection at the same time with wdtv live?

I planned to buy a Synology with 5 x 3 TB, but now the prices on hdd rise as we speak. A solution is a 2-bay nas with esata. I have 4 x 4tb My Book, and thinking the nas can connect with wdtv via ethernet and two My Book connect on the two esata ports on the nas and the other two My Book connect to the usb-ports on the wdtv. will that work?

Well, if the two drives that you will connect to the NAS, via eSATA,  can be added as shares, your setup should work.

Instead of connecting the NAS directly to the WD TV ( I have not try that) why not connect the NAS to your network?

Thanks, connect the nas to the network, off course.