By implication it is positive for the Trump campaign and means there was no conspiracy with these actors- if there was a broad conspiracy there would have been no need for these Russians to hide their identities from their Trump counterparts.
This means that any conspiracy must be limited in scope rather than broad (i.e. Mantifort)- it doesn't completely clear Trump (and proving a negative like that is of course impossible anyway) but it is unambiguously more positive for him.
No it doesn't. Saying that on a certain day there weren't any clouds in the sky does not mean that for a whole month it didn't rain.
There is absolutely no implication or suggestion of any kind in that statement that indicates no conspiracy on the Trump side.