Error W4134 is issued from 2 places in the coding. At one time it checks for existing valuation type views. This is a warning and may go away if other errors for this material are resolved.
Make at least sure that all MBEW records for this material have a deletion flag.
And OSS note 561972 explains the reason why and when this message is issued as error message.
re Q5
Archiving cannot be done at item level, please do not even try it you only create inconsistencies.