I meet up with a friend and we talk about how a neighbour will be away on vacation soon. We talk about getting a crowbar to break into the place. Not illegal.

Where that storyline stops, that is correct, the speech is not illegal.

I meet up with a friend and talk about getting a crowbar to rob a place. I go to the store and buy a crowbar. This is now illegal. It has become a criminal conspiracy. Whether or not I actually rob the house does not matter. A criminal conspiracy has been committed.

I believe that, under GA RICO, two qualifying criminal actions must have taken place (within a timeframe of four years) to advance the conspiracy. Neither "talking about robbing with a crowbar" or "buying a crowbar" on their own are criminal acts, and so this could not be charged as a conspiracy under GA RICO.

However, if you got another friend to come over, without knowledge of your first friend, and convinced that other friend to go steal a crowbar (coercing another person to commit a crime), and that person stole the crowbar (theft), even though the other friend had no idea about what your plans for that crowbar were, those would be two qualifying crimes in furtherance of a criminal conspiracy, which would be chargeable under GA RICO. And then your initial conversation where you first only talk about breaking into the house with a crowbar is illegal, as part of that conspiracy.

Even though your first friend had no knowledge about your talking to a third party about the crowbar stealing, or the actual crowbar stealing, they are still part of the conspiracy, and can still be charged under GA RICO. Even though your other friend had no knowledge of the first friend, or the intended purpose of the crowbar, they can still be charged under GA RICO. These two friends of yours don't even have to have any knowledge of each other's existence whatsoever.