The antenna in your attic reminds me of this style, popular in the 50's when TV was exploding in suburbia.
If it were me, I'd focus on the Philly stations, and since they transmit on all bands, all the way down to real channel 2, I'd just use a (new) full-range antenna pointed at about magnetic 30 degrees, mounted in place of the old one. I don't see anything in the Atlantic City market that you can't get from the Philly stations.
I'd also run new cable outdoors, at least to one TV for initial setup, and look into reusing some of the old stuff once it's working to your satisfaction. I would not wire up the whole network, especially with old cable and splitters, before establishing what the system can do in its cleanest configuration.