Your CM4228 is limited to reception of real UHF signals. As you read your TVFR, pay attention to the Real Channel column, not the virtual channels (antennas know nothing about virtual channels).
Your TVFR contradicts your description of a clear line of sight to Mt. Wilson. Example:
KABC path profile and
KCBS path profile
Your idea of using an XG-91 and YA1713 with your CM7778 is not overkill IMO. Adding the YA1713 high-VHF antenna should give you KABC, real CH-7, KTTV, real CH-11, KCOP, real CH-13 and KCAL, real CH-9. If you're not seeing KCBS, real CH-43 now, you'll need a better UHF antenna (the XG-91) and maybe higher mounting.
If KUHB, real CH-6 (an analog TBN translator) is of interest to you, a separate low-VHF antenna can be added. Otherwise I disagree with the suggestion of an all-channel antenna, particularly an antenna with less than maximum UHF performance, which you'll need to have a shot at KCBS.
PS. DL got his post in just ahead of mine... I think we are very close to agreeing on this one... KCBS is going to be the most challenging 'get' in this case. I'm hoping the superior directivity of the XG-91 and it's higher gain will be enough but you won't know until you try.