Hi @ana_RODILES,
Thanks for posting.
PCoA biplots are not yet supported in q2-emperor, but we have an open issue here tracking progress on that feature. For now, you should use qiime1 or phyloseq to make biplots. It should be fairly straighforward to export your data from QIIME2 into formats that qiime1 and phyloseq can consume (e.g., biom tables or possibly even distance matrices) — please see the data exporting tutorials for more information. A number of forum posts (e.g., here) have also covered exporting specific data types for use in phyloseq, so searching the forum may assist in this process.
Could you please post your second and third and fourth questions to separate posts? This will make these issues easier to answer and track, and for other users to search for help in the future. Thank you!