I will be there then as well. IMO no. They will keep it closed while they work on Sago. If you have used the walkway you will remember that there is a parking lot adjacent to the start of the walkway near the end of sago. That is where they will be bringing in equipment etc.
Also it takes months plural to do one building so I don’t think they will have time. Perhaps Memorial Weekend or in June is my guess. It could be longer ….
Also I just remembered they still need to do the Main building guest rooms and I don’t know if the walkway will impacted by that. However mono to MK is fast and then we use the boat for returns for the most part.
If concerned about leaving after fireworks etc with crowds what dd and I sometimes do is walk to CR and hop on mono from there. Occasionlly getting out of MK can be a pain and this option worked better.