He's told INS/ICE to concentrate on criminals.
And to ignore everybody else. Obama straight-up doesn't care about enforcing the borders. The donors want cheap labor and the Democrats want voters.
I doubt that banning all Muslims would pass muster with the Supreme Court.
There's no reason to believe this is the case, and many legal scholars have already said it's fine. We've done similar things in the past. The free exercise clause applies to people within the jurisdiction of the US. When we deny a visa because someone is a muslim that person is still in Yemen or wherever. He could also just deny visas to anyone coming from certain problem nations, which would have a similar effect.
He can renegotiate trade deals but they still have to pass Congress.
It depends. A lot of trade deals have conditionals in them that allow the executive to modify them. For instance, just declaring China a currency manipulator would go a long way.
As CiC he still has to work within the budget and authorizations that Congress gives him. Obama has tried to get a new authorization for use of force against ISIS but Congress refused.
We're still bombing them, though. We can stop doing stuff like dropping leaflets warning them of our attacks like Obama's been doing. We can start coordinating with Russia, instead of threatening them.
My point stands, of all the candidates, Trump is the candidate whose proposals require the least amount of Congressional involvement. And even most other things aren't that big a deal. If the puts forth a plan to tax remittances to Mexico to pay for a wall...that's just not that big of a deal. A $10 billion public works project funded by taxes on foreign workers is nothing compared to something like Obamacare.