Interrupting a cast of Embrace in order to cast Embrace on someone else is impossible. Please take a couple minutes to re-read that section as that may help clarify what this macro is designed to do.
Correct. Faeries do not have the ability to queue and a macro can't fix that. My "queue" macro is basically a macro to automate the repeated pressing of the button that most players do manually.
You can still do that. I still have an embrace macro without Physick that I had been using long before I discovered the range limitation and decided the Embrace+Physick macro was a good idea. You can also use an Embrace+Physick macro while you are casting something else or moving and while you will be unable to cast Physick, your faerie will still do Embrace.
If you are saying what it sounds like you are saying, this is a horrible idea. Once your faerie starts casting Embrace, her GCD for Embrace is spent, whether she finishes casting or you interrupt her. Eos will not be able to re-cast Embrace until her full 3-second cooldown has finished, same as if you had let her finish. All you are doing is throwing away a casting of Embrace for nothing.
Worse yet, the moment her cooldown is up, if auto-cast conditions are met, she will immediately start casting on her own. If you are for some reason bound and determined to make her heal someone her AI wouldn't choose naturally, this will not accomplish that.
This is all very easy to confirm by testing your macro outside of battle.
To be honest, the only times I have ever questioned her decision to heal someone and wanted her to heal a different target have been when things have been going REALLY badly, a lot of people are low on HP, and I have to start choosing who to save and who to let die (save the tank, let the DPS die). Those situations are very rare and usually end up in a wipe anyways. The rest of the time, I find the auto-healing to be very helpful. I don't understand why so many people want to eliminate auto casting or manually override her choice for Embrace.