Your assessment of your reception situation is correct. It is complicated with no easy answers , Some answers are a loop that lead nowhere , and hard to find information.
Most the Tv stations are to the north west. So with 1 antenna to start with , install the Winegard HD7084P antenna aimed at about 330 degree magnetic compass. Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html ,
Also for those Very Weak digital Tv transmissions , install a
http://www.kitztech.com , Ultra Low Noise Amplifier , Model KT-200-COAX TV Antenna Booster Remote Power Coax Fed amplifier.
Install a 2 way splitter for 2 Tv's. A 3 way splitter for 3 Tv's. A 4 way splitter for 4 Tv's. . . All of the Kitzteck amplifier can installed in the attic , most attics have electric power to plug the amplifier in to. That way none of the amplifier will be in the weather.