Hello Chris,
what stakeholder matrices/tools are you referring to? If you mean generally what we do to build a good relationship with employees of acquired/merged company, then we run regular integration calls/meetings to ensure that new employees (of the merged or acquired company) understand their position/function, we issue internal bulletin to report on process of integration so each has a visibility, we run regular Q&A session, we involve new employees very early in all diversity/integrity and similar processes to create a momentum.