ROBS can be a tricky transaction that not a lot of CPAs or Legal experts have experience with. That’s why we recommend working with a ROBS provider and take advantage of their free consultations to ask questions like this of experienced professionals.
Now, a C-Corp can own multiple LLCs but you must set it up correctly and abide by the rules so that it doesn’t cost you a lot of money in the long run. These businesses will need to be separate and you may not be able to roll all of the tax obligation back into the C-Corp. You should discuss this with experienced professionals who can adequately help you prepare for your unique situation. Good luck!