Question about WD Red Plus

Hello all I bought some 8TB disks (WD80EFAX) a few years ago: https://www.digitec.ch/de/s1/product/wd-red-plus-8-tb-35-cmr-festplatte-8766619 Now I'm wondering if they are compatible with this one (WD80EFZZ) in a RAID5 from my NAS without exception, especially regarding buffer size and Max. Speed. Respectively how does it behave? - Do all HDDs rotate at the slowest speed in the RAID (i.e. 5400 rpm)? - Is the buffer size limited to the lowest (i.e. 128mb)? Thanks for a short feedback and have a nice day!