How do I populate fields in content type not in feed when importing?
You can use the Feeds Tamper plugin "Set value or default value".


Install the modules Tamper and Feeds Tamper.
Go to the mapping page.
Select a target that you want to set a default value for.
On the source selector that appears, select "New CSV source". Type in a source name that does not appear in your CSV file.
Repeat step 2 and 3 for every field you want to set a default value for and save the mappings.
Go to the 'Tamper' page.
For each target you want to set a default value for, click on "Add plugin". From the selector that appears, select "Set value or default value".
A field called "Value" appears. Fill in the default value and click "Submit".