A: Columns is a lightweight BI.
It does not support data modeling, which means it processes single data sources only, such as a CSV file, a Spreadsheet, a Notion database, an Airtable, an SQL query (to your DB), from there you will build data stories to share.

IF you can mix up all your data into a single data source, then yes, otherwise, you will have to connect each source separately build from each source independently.