After briefly browsing GMU’s offerings, I’d think that this program would appeal to you:
Bachelor’s in Bioengineering with the Concentration in Neurotechnology and Computational Neuroscience (NTCN).
That kills all your birds with one stone, for an in-state price, and avoiding the absolute slog of doing a double major in your fields of interest. Also, a double major would almost certainly require an extra year, which can be expensive.
Are you interested in that program? And if so, have you been admitted to the college of engineering at GMU?