This is a circumstantial evidence thread. Circumstantial evidence cases are very hard to win in a court of law. Just sayin'. Without direct proof at any number of these instances, this woven 'garment of proof' falls apart.
Given all of this, however ... Mueller and his grand jury have their work cut out for them. If there's a thread, they'll find it, yank it loose ... unravel and burn it all down.