Buying a business with an illegal worker

I am looking at buying a cake decorating shop in Texas. I want to ensure that a particular employee stays at the shop. In order to do so, I was planning to form a partnership of some kind with her - probably an LLC. She is a Canadian citizen who is here as a dependent on her husbands TN visa. She is waiting for a green card, but evidently that has been going on for years. She has been working illegally for the shop for a year. My question is what kind of Visa would she need to get - TN or H1B in order to work for a business as a LLC partner. My other fear as that 'cake decorator' does not seem to qualify under the professions listed on the approved occupations lists. If there is an option, what is it likely to cost in lawyers fees and application fees and the duration of the process? Thanks for your help!

It needs to be a real profession. Cake decorating certainly won't fly. Maybe as a Manager? Or accountant for the store. Only thing is, she would need education and experience to back it up.

... and she could not be a partner.