I think that the fact that Alice's resell is covered under the first sale doctrine does not affect Bob's right to request from Alice the source code of the binary that he had just received. Besides, it's reasonable to expect that Alice is able to provide such a copy, so it can't be seen as a restriction on Alice's right to resell.
If you are doing something with GPLed software that does not require permission from the copyright holder, GPL does not apply to what you are doing.
The significance of the first sale doctrine here is that if it applies then Alice's distribution of the binary to Bob does not require permission from the copyright holder.
