If Hitler had been killed would the SS have stayed loyal to the regime?
One of the reasons that the plan Bonhoeffer was involved in did not go forward was those involved could not get the head of the Army (Keitel, I believe) to agree not use the Army (this would be the old school Army leaders) to stand down as those plotting assumed leadership over the Nazi segments. That would include the SS.
The plotters feared a civil war could break out between the Nazi/Hitler loyalists and the Germans who were simply true Germans (i.e. not Nazi's).