Using subcontractors on invoices

I am new to Quickbooks (and accounting) and am trying to understand how to use subcontractors in this software. I have read other forum questions but they don't seem to be specific to what I am trying to do. I use subcontractors as part of the installation for a product I sell, and they give me a quote for each job. Questions:

1. I don't upcharge the contractor fee, I just pass it on to the client. So when creating the product in the "Products and Services" for the subcontractor fee, is this categorized as a sale or an expense on the income account since I am selling their services but I don't profit anything from it?

2. Since the contractor is a company and not an individual, do I charge tax on their invoiced service to the customer since I assume they charge their own taxes when they give me the quote for the job?

3. Since the contractor is a company and not an individual, do I still need to create a 1099 for them like if I was using an independent contractor, or do I set them up as a vendor and don't worry about the 1099?

Thank you for your help!