See, this is exactly why I didn't understand why in the world that your Vet wanted to wait until October to put the implant in...I have no idea why he thought that having surgery would cause her to not be hormonal for months and months afterwards, but obviously it didn't, lol...I mean, it's pretty basic physiology, just think of a human woman who has surgery to remove her Appendix, or to repair an abdominal hernia, or to take out a kidney stone or her Gall Bladder...She's still going to get her period the next month, or the same month if she hasn't had it already. The only surgery that will stop her from getting her period or stop a bird from being hormonal is going to be one to remove both of her Ovaries, lol...
You're doing everything the right way, you're not doing anything to encourage her hormones at all, you've got her on a Natural Light Schedule, you're not feeding her any mushy, warm foods, you're not petting her belly or under her wings, and you removed the "Hut" and she can't get underneath any furniture or inside of any cabinets or anything. Not much more you can do...You also have to remember that when her body formed that egg that was too large for her to lay, it was produced from lots and lots of Follicles. So she likely had other Follicles when she had the surgery to remove the egg, and she could have even had another egg forming at the time that didn't drop into the Oviduct, obviously because it couldn't due to the huge egg being stuck in there. So I'm glad that they are doing an X-Ray on Wednesday to rule-out another egg...
If she does happen to have another egg in her Oviduct right now it's not necessarily a horrible thing, most eggs that they form are not anywhere near the size of that one, that was one of the largest eggs that I've ever seen come from a Sun Conure or similarly sized bird, it was just massive. That's not the norm, and since it was the very first egg she's ever laid in her life, that could have had something to do with it's size, I'm not really sure on that honestly. "Firsts" for birds usually do go wrong, like the first clutch of baby birds a breeding-pair has when they've never been parents before, that often goes very wrong for a million reasons. So if they take the X-Ray on Wednesday and she does have an egg in her Oviduct, they'll also be able to see it's size and be able to tell if she's going to be able to lay it. If it's small enough that she's able to lay it then they'll hold-off on putting the implant in because it will interfere with her laying the egg, and they'll probably give her another shot of Oxytocin if the egg is in the Oviduct and fully formed/hard-shelled and ready to go. Then as soon as she lays it she can have the implant put in...If she would happen to have another huge egg in her Oviduct, which I highly doubt, there are other ways that your Vet can do besides opening her back up again to remove it, he's not going to want to do that again this soon, she's not yet recovered from the first time...So more than likely he would do the procedure to drain the egg's contents through her Cloaca and then remove the shell piece by piece the same way, which is not an invasive procedure at all and when it's done it's done, there's no recovery from that procedure...The only reason he didn't do that the first time was because of the risk of egg-yolk peritonitis, but now he would have to do it...
Just hang in there, chances are that the X-Ray on Wednesday will at worst show some Follicles present, which will not delay them putting the implant in. And then within 30 days all of these hormones will be gone and so will your constant worry. But I have to say that I'm thrilled that you chose to request the Vet put the implants in now instead of waiting until the fall to do so, because this is exactly the reason that I suggested it to you...It's very common for them to become hormonal right after having an egg removed, in fact it's really the norm because where there was one egg in the Oviduct, that means there were many more Follicles where that egg came from...