Personally, I think you have the right attitude. You are trying to keep everything legal and straightforward, which is a good thing. Becoming an employer is a big deal, and you should plan carefully.
If you plan carefully, it might be possible to avoid the revenue issues with subcontracting. I don't know your business though. It might take some planning and cooperation from your subcontractors.
When you think about it, it might make more sense to take on 5 or 6 people at the same time, including an office administrator/HR person, rather than adding people in dribs and drabs and never having any real system for managing the growth.