Well after you bond with your bird and you have had it for over a year, then you can leave for several weeks and they should not be affected. Some of them here on the forum have done that very thing, and they returned to no problems, just a happy bird, glad to see them.
So if your breeder can keep the bird a little longer, I think you will not have a problem, then when you get back, get the grey and bond with it before going off on another long trip.
The feather plucking can be caused by different things, but I wouldn't worry about it at this point, if you pay attention to a lot of the information we have here, you may never have a problem.
Now even though you do not have the bird yet, you can still introduce yourself on the welcome page, we would like to know a little more about you, helps us feel more like a family here.