OK, I see that the answer to my Queston 1 in How to install the latest metaphlan reference DB? - #14 by rda is provided in:
By default, the latest MetaPhlAn database is downloaded and built. You can download a specific version with the
--index
parameter$ metaphlan --install --index mpa_vJan21_CHOCOPhlAnSGB_202103 --bowtie2db <database folder>