Hello again! With the new motors, the remote and code functions properly, so I really appreciate the help with that issue.
However, I ran into a new problem. I took slipstick's advice and got a bigger power source. The one I was able to find readily available was 8 x AA batteries for a total of 12V power supply. The motors still have trouble rotating on their own, so sometimes I need to provide a physical tap to the propeller in order to get the motors rotating. The power supply is attached as shown in the diagram in the link above, with the positive and negative hooked up to the +/- runners on the breadboard.
Has anyone run into this problem before and/or have any ideas on how to fix it? I wasn't able to find any explanation online before posting here.
Thanks for the help!