Hi @sdpapet ,
Your questions have all been answered already by @timanix here:
this answers your questions 3+4 directly, and if you read the documentation at that link, you will also find that this same command works for visualizing a variety of data types: sequences, taxonomy, and feature tables, either alone or together.
Otherwise you can use qiime tools extract if you want to pass the data to other software outside of QIIME 2, e.g., for @wburgess 's suggestions here:
Good luck!