The reception equipment seems OK. I have the Samsung box and it's great.
I see KABC, KCOP and KCAL on VHF-HI (7-13) on that list. Those signals look strong enough you should be able to do with a fairly small antenna despite the distance. The CM4220 might work for UHF, but it's a lousy antenna for VHF-HI. I have the Winegard HD-1080 on my roof and my VHF-HI reception is great. UHF reception is a bit worse than the CM4220, it seems, but it is great nevertheless.
Stark Electronic has it for $35. Winegard also makes higher-gain 7-69 antennas that are likely to work.
It's tough to say whether it'll work. If the only thing that concerns me is the split to two TV's of distant signals. If it works without a splitter but breaks up with one installed I'd recommend a higher-gain antenna than the HD-1080. They are strong so that might work, but I don't know. I'd replace the cables while I'm at it to ensure a longer life for the system.