The Feds don't think there is immediate need to raise the rates even though the data coming out are encouraging. They are just hoping that the economy can stand up without any more baby sitting QE''
What happens if the FEDs err? And they can err in two ways, namely by removing the punch bowl too early or too late. If they remove it too early then the US will fall into deflation. Alternatively, if they remove it too late then the US will have inflation. Now, the question is: of the two which one is easier to cure? And the answer is: inflation. If so, the correct policy is to wait until inflation expectations become a bit entrenched.
As to your question about what the FEDs will do to their portfolio of T Bonds when the need for monetary stimulus goes away is something we can only speculate about as to begin with we don't even know what kind of 'normal' the US is going to be in
