What's included in the pinion set i.e. bearings, circlip, also what's included in the housing or is that bare?

If you are able to look at the below diagram it shows the set of pinions include items 6-9: The gear housing includes items ​1-5 and 18, please see the below drawing: https://www.lsengineers.co.uk/gear-head-0-assembly-for-stihl-hl100-long-reach-hedgetrimmers.html