I am not sure how and when the Trump plan will work out. It seems that the Fed and Powell are his biggest enemy of him. Maybe he has a bigger challenge to have the Interest rates cut than to have the tariff negotiations with China. In less than a month, he has emphasised enough on rate cut, but Powell seems least interested. He never hinted that he is interested in the Interest rates going down anytime soon. The below is the newest tweet from Trump again hoping for the cuts. 
Well, Powell can't cut rates now. Especially with tariffs in play. Would you imagine a weaker currency (USD)? That would raise the cost of imports more than what they are right now. The FED should be raising rates to make the USD stronger and imports cheaper. But I'm no economic expert, so please correct me if I'm wrong.
Either way, Trump's dreams might soon become a reality as Powell's term comes to an end. There could be a new FED chairman that's a "Trump loyalist", putting the central banks' independence at risk. Americans are headed into economic uncertainty. So they should prepare themselves for the worst.