Is this a sign republicans in congress may do something?

Only a carefully selected subset. Just enough of the most vulnerable of them so they can be on record as being against this, but not enough of them to change any outcomes.

I wouldn’t be surprised if we get enough Republicans in congress to pass a law taking the tariff power away from Trump, but Trump will veto that law.

I would be quite surprised if we can get enough Republicans to override that veto

No, Mike Pence is a villain to Trumpist republicans. He speaks for the old guard republicans who still think this is all just a temporary blip and populism will be forgotten in 4-8 years.