RE: 2.4 GHz... Will one transmitter work with other brand recievers?
There are no 3rd party 2.4 receivers. You cannot, for example, use a Futaba 2.4 Rx with a JR/Spektrum Tx. JR and Spektrum use the same technology, so you can use a JR 2.4 Tx with a Spektrum Rx and vice versa.
I believe that the DX5 is DSM. You can use a DSM Tx with a DSM Rx, but you cannot use a DSM Tx with a DSM2 Rx. You can use a DSM2 Tx with a DSM Rx. DSM is an earlier version of Spektrum technology. DSM2 is a later version. Be sure to check and see if the Rx you plan to use is DSM.
A Bind n Fly airplane comes with a JR/Spektrum compatible Rx. You could buy the same aircraft in a Plug n Play version, which does not come with an Rx and allows you to put in whatever Rx that is compatible with your Tx.