Hi,
Rowland33 is right.
You have to have a general view of the problem beside the details.
For the details i have no problem they are easy to solve.
For the general view,
For this structure the beams could have other behaviors,
are this beams acting to take lateral forces by now, because when you take out the column is going to take nothing (to long the slenderness have made his work)
Once you replace this two columns the behavior of the building is going to have a drastic change. Have to take an aditional analisys to verify.
Have you think about a safe process of work, do you think that in this process is needed aditional calculations to have no risk?