I don't know if they are shopping Havenstein so much as perhaps just in wait-and-see mode with him. See how the top 3 rounds play out, who they do or do not add on the OL by the end of day two. That could dictate their appetite for keeping him and trying to trade him for a day 3 pick.
And then yes, his status (still with the Rams or traded) then dictates what else they might need to do with the cap. I believe they would like not to restructure Goff if possible since, as it stands now, his number as a percentage of the cap goes down in 2021, 2022, etc.