I think you should review Luttig's remarks on the issue
I believe there is a two part reading which is an important distinction. First is as you say, the actual insurrection. According to the 14th amendment, an insurrection lead by or perpetrated by people who have not taken an oath to uphold and defend the Constitution, would not be covered. These folks would be covered by existing laws regarding insurrection against the United States. Second would be those who had taken an oath to uphold and defend the Constitution (as is the case of Trump) and participated as outlined by the 14th Amendment, those people would be held accountable according to the 14th Amendment, which would mean inability to run for or hold elected office.
Apparently the Shaman can run for office in AZ and not be taken off ballot for his participation in insurrection, but Trump because he allegedly (according to public records and evidence) participated in an insurrection can not run for elected office according to 14th Amendment.
So, what all of that means is, it is not necessary to prove he led the physical insurrection at the capitol, but rather demonstrate he participated in a plan to subvert the Constitution by promoting fake electors and stopping the Constitutional proceedings. There is enough public records and evidence to sustain the allegation, and therefore we should conclude Trump should not be allowed on the ballot.
As to the issue of timing, I suspect you are correct. It would be better to use the evidence which Smith has found and then file suit. However, the issues involved are more complex than at first reading. There is too much ambiguity in the language for mere lower courts. It will have to be brought before the Supremes seeking their imprimatur.
