It's not that I don't want to use IDs, I would if I could, but it's impossible to get all the relationships between-> Name -> product.product_category_17. That's what my export prints out when I do a test and there's no way I can know what id is what for the suppliers and the categories.

I also don't know what you mean by use just categ_id...I have only three options to choose from when trying an import (Category, Category/External ID, and one more but it says ID). I've tried all three and none work with a string.

The Categories and Suppliers have to be imported first, before products - have you done that?

These are already created and available when editing or adding new products.

OK. Create one record manually, via the UI, and then export it. You will see from the CSV what format the data needs to be in and how you can set categories.