Box 1: Yes -
Once you have defined a skillset, you must map the output fields of any skill that directly contributes values to a given field in your search index.
Box 2: Yes -
The definition is a custom skill that calls a web API as part of the enrichment process.
Box 3: No -
For each organization identified by entity recognition, this skill calls a web API to find the description of that organization.
Reference:
https://docs.microsoft.com/en-us/azure/search/cognitive-search-output-field-mapping
