If the drugs, particularly highly addictive drugs, are free flowing into the country the first that needs to happen is interdicting the flow. Everything else you speak of is secondary. Border security, migration controls, striking the production sites and people involved.
I don't know about that. But I think if the US really wanted to, they could make a massive impact (probably impossible to completely cease it). The US just needs the right political leadership to do this, and with Trump they will have it.
Special forces, intelligence, advanced technologies, but most especially the political will would be able to achieve this no problem.