Didn't Picard state in "Q Who" that the Borg now know about the Federation because of the events of "Q Who"? It was never established that a transmission of any sort brought the Borg to the Alpha Quadrant, AFAIK.
When Cochrane looked at the Enterprise-E in the telescope in ST:FC, I admit I did have the thought that the saucer/nacelle configuration of all future Starfleet vessels was born then. There was nothing leading toward that design configuration up until that point. Cochrane did have a 2-nacelle design, but nothing to lead toward a saucer shape for the crew portion of a ship.
When you think about it, how could the things he and Lily saw not
affect their future activities & decisions? And it's not like they were unknown bums in an alley accidentally phasering themselves. They were very influential people in what was to come.