I am the Chair of the Libertarian Party of Hawaii.  The Koch brothers are not "bankrolling" the LP ticket.  If they were you'd be seeing it in terms of millions of dollars in pro-Johnson ads. The Koch's do support a network of libertarian oriented organizations.  Many of the people involved in those organizations may be helping the LP on their own.  
The Johnson people believe they will be on the ballot in all fifty states.  The last deadlines are in August.  
The debates are controlled by a bi-partisan commission of Republicans and Democrats who may find reasons to keep third parties out.  The national media should never have allowed these two to have such power. 
Finally, the column did not mention the Green Party nominee by name. I believe the presumptive Green candidate is Jill Stein.