It does work. If you don't have mapping saved then it won't display the list. I tested on https://demo.circle-interactive.co.uk/ after saving the mapping. Second time i visited the page i could see mapping field. Make sure you have mappings saved for contribution export.
The issue is almost certainly that the "County" field is not enabled by default, which suppresses it in the import dialog.
Go to Administer menu > Localization > Address Settings, and under "Address Editing", see if the "County" box is checked. If not, check it. Restart your import and the field should appear.
I also confirmed your report that County ...
You will not be able to do that with the GUI since it lists the matched pairs but does not allow to export it in a configurable way.
Your best bet will be to use the API (that means programming in PHP), and specifically the entity Contact, action duplicatecheck. Here is a sample code:
$result = civicrm_api3('Contact', 'duplicatecheck', array(
Welcome to CiviCRM!
For the import of Boolean fields (yes/no, true/false, check boxes, etc.) the correct syntax is 0 for no or false and 1 for yes or true. Use 1 instead of Y or YES, and it should work for you.
Be aware that your imports thus far may have created NULL values in the database. See this question and answer for reference: https://civicrm....
You're half way there with this. I would say that the three types of people are 'Contact Types'. Groups and/or Tags can be used to break these down where relevant, for instance, tags might be used to identify who actively contributes to your org, and groups might be used for the people that you will be mailing newsletters to.
The rest are probably mostly ...
There is a very useful extension called "Extended Reports" that has an Activities report that allows you to pull information about the Source, Target and Assigned contacts, but if you are looking for information about an organization that is related to one of those contacts but is not directly linked to the activity (and you don't have access to a developer),...
I don't think there's a way in the UI to update the order... I would suggest creating a small mapping and reordering it in the database (I agree that the column_number is the likely candidate - interesting that it's not weight as in so many other Civi features) to confirm that will work.
Good question. I am sure in the 'old days' you used to be able to work you way back to such a list via the breadcrumbs, or maybe i am confusing it with Option Groups. But i just gave it a go and couldn't find a way to it.
Your best bet is to jump in to the DB if you have access and grab a copy of the civicrm_custom_field table, plus the civicrm_custom_group ...
I would double-check that the none of the custom data that you are importing exceeds the length constraint set for those custom fields, and raise that constraint if necessary for the long fields.
I believe default is 255 characters for most, and I believe that includes all options for multi-value sets smashed together, not just 255 characters per option.