HDD Failure in WDBLWE0080JCH compability WD40EFRX vs. WD40EFZX vs. ‎WD40EFAX

WD External Drives External Drives for Mac
#1

one of my two WD40EFRX hard drives failed in my WDBLWE0080JCH, is it possible to replace it with one WD40EFZX or ‎WD40EFAX or does it cause Problems if I run for example a WD40EFRX and a WD40EFAX in a RAID1 configuration?

#3

Thank you, but this wasn’t the answer to my question.