Not all of these will investigate the same issues and scandal subsets. The Senate Judiciary Committee, for instance, seems to be the only one investigating the potentially illegal quid pro quo promise of American visas to Chinese investors involving the family of Donald Trump's son-in-law, Jared Kushner (details here).
In other startling developments yesterday, yet more Trump key players were revealed to be under investigation for possible Russian collusion. Trump's personal lawyer is now being investigated and is refusing to cooperate with the House Intelligence Committee (details here). And former Trump loyalist Boris Epshteyn is now being investigated as well (details here).
On the same day, only hours apart, both Trump and Vladimir Putin attempted to push back against the avalanche of scandals with the same talking points: it's fake news being orchestrated by Democrats. If that was true, why are so many Republicans spending so much time investigating all of these scandals?