The average benefit percentage is calculated by considering ALL contributions to ALL plans within the CG, so the only people with zero rates anywhere should be those with zero deferral, zero match, and zero profit sharing/safe harbor/non-elective. Groups 1 & 2 are only zeroes for purposes of determining rate groups under the general test for nondiscrimination, which you should not need to do. If Plan 9 satisfies coverage and provides uniform percentage (design based safe harbor), you should be good, but you have one average benefit percentage for the entire control group that is based on all contributions.
Yes, be mindful of BRFs.