Let's Be Precise

I see the statement that "Mueller didn't find any evidence of collusion" or words to that effect.  We don't know that. With a layman's knowledge of the law I think there are these possible points on the continuum of incriminating evidence:

• no evidence at all, meaning the investigation was launched without solid cause.  (Might have been bias, might have been false evidence, might have been facts which seemed to point one way but actually pointed another.)
• some evidence, but not enough for the prosecutor in the case to take to trial.  (I'm assuming that different prosecutors will be more or less cautious in what they take to trial, or try to get a plea deal.  I note Jerome Corsi was offered a plea deal, which he turned down.  Were the prosecutors bluffing? )
• enough evidence to take to trial.
• enough evidence to convict, given the prosecutors, defense attorneys, jury and judge in the case.

What the Barr memo says is Mueller couldn't get to the third level.

I also note the Barr memo includes the phrase "Russian government".  I assume that allows for possible difficulty in determining whether person X is an agent of the government, directly or indirectly, or is a "cutout" as we know from films and books is often used in spy thrillers.  I'm not clear, however, what difference it makes: there's a crime to conspire with a foreign government but not with foreign individuals?