Do I need to define a field for each of these attributes
You need to define all the fields any way if you want to retrieve their values.
Should I be copying them all into one field so I can search across all those fields? This is necessary right? You would need to copy them to a single field and search over that field.
Is there a way that I should just import all of these fields into one solr field? How should my schema.xml look?
you can define dynamic fields and have a single copyfield to copy them to a single field