Nobody knows what the near future will bring to us. As we see with every day Turkey becomes more and more confident regarding those issues but I don't think such a thing will happen very soon. Also it is not sure how the current Turkish government would take on the Kurdish issue. Tomorrow maybe we will wake up as federation because all their moves are pointing for that such preparation is being done. If they could counter the separatist movements its not so bad idea but if not it is suicidal.ISF tried to take it late 2017, American pressure stopped it from happening. Iraq can take it militarily easily as it is close by current ISF line but they need a strong reason to do so, such as heavy Turkish pressure that gives Baghdad an excuse in the face of Americans.
Although Baghdad taking Fishkhabour is one thing, closing the border between Fishkhabour and Syria (rejecting American movement) is another which would mean Iraq blocks the American project in northern Syria, whilst legally allowed to do so it would anger the US leaving them with no other alternative but to accept that fate or to be hostile to Baghdad.
Dangerous situation.
The new border proposal is to bypass the KRG customs/tarrifs, KRG will cave in to that demand eventually as they seek it.
http://www.rudaw.net/NewsDetails.aspx?pageid=394303
Baghdad will only reopen Erbil-Kirkuk road if it gets a customs border
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However what I do not understand is why Turkey doesn't use Iraq to counter the SDF/YPG project in Syria. Simply by making an offer to Iraq, setting up the atmosphere/pressure/support in some aggressive manner which Erdogan is good at that would let Iraq make the move to cut KRG from Syria whilst saving face in front of the US. Since this is such a big problem for Turkey, either they aren't considering that or doing so is not possible given the move would would meet strong US opposition. Sadr is a good candidate for such a thing as he's a strongman type of leader who doesn't like Americans and would rather work with neighbors.
We see that DEASH is being destroyed and little work still have to be done in that matter. We see that the environment in Syria is slowly setting up for a political and reconstruction process. Maybe when the situation in Syria settles up and the conditions are being clear of what will be done then such move can occur. I don't think that Turkey or Iraq will close the US corridor to Syria at the moment as both are members of the International Coalition against DEASH and that would mean "sabotaging the international efforts in the fight against DEASH". Every move against the US in Syria at the moment is complicated matter.
While everyone will take something from that war I think that the US will take federation and maybe US bases on Syrian territory. If the areas that will be under the control of Kurdish factions move for independence then I think that Turkey would act harshly and wage war otherwise we are countered into the corner. We must hope that Syria doesn't go for partition.