Presuming these are USB HDDs then you could add them to either Z9X or Z10 Pro. Unless you want to use the internal SATA bay on Z10 Pro, Z9X would seem the better choice.
You are unlikely to run into power problems with the two drives connected by USB, although if you do you could add a powered USB hub.
Z1000 Pro, UHD3000 and NEO S do have higher amperage power supplies so would ultimately be better for multiple HDDs.
Zidoo produces better picture quality compared to Shield. It also supports more formats and is more configurable.