Questions Importing Parent Customers, Child Customers and multiple Locations

To give you my experience

1. If I want to import a customer with a parent and many locations, is it correct to assume that I would import the Parent Customer(s) first. Then after they have been successfully imported I would be able to import the Customers with the Parent field listed in the spreadsheet?

Yes I would take this approach

2. It seems, from looking at how a Customer is added manually, that I am unable to control the creation of the first location through import scenarios. Is it correct that when importing it will always create a default location MAIN?

Yes you are correct

3. How would multiple Customer Locations be imported? Can they be brought in with the Customer data or do they need to be imported separately?

I would take that approach as well, I do the same with contacts - import them separately 

4. How do you import Attributes? If I do an inspect element on the attribute value it doesn't give a field name. Are there any articles about this someone can refer me to?

Try this, not sure if the changes in version 6 or 2018 broke this article

https://myobexo.custhelp.com/app/answers/detail/a_id/38421/kw/import%20attributes/session/L3RpbWUvMTU0Mzg4MzIxOC9zaWQvcmRBUmFvMW8%3D

As you are aware the import scenario mimics data entry and work when the data being imported is relatively flat.

Thanks