It does mean that his input needs to be fully corroborated and vetted. Of course.
The documents he provided are a pretty good start. As is the timeline.
But, it does seem absolutely clear he worked closely with Rudy. Also clear that Lev was able to obtain audiences with Ukraine's highest echelon players. How does that happen unless Ukraine believes he is Trump's envoy (through Rudy).
Lev worked for Rudy. Rudy is Trump's personal lawyer. Rudy was carrying out Trump's marching orders.
Trump needed dirty operators, knowing that career State Dept employees would not have carried out unlawful orders.
Not real complicated.