Per the FTC filing, many of these are not relevant for deciding if illegal price fixing has occurred.
It doesn't matter how the algorithm operates. If all landlords in an area publically agree that they will set rent prices at 400xx the price of a coke can, they are only using public information, but still engaged in price fixing.
It doesn't matter how many people actually use the algorithm. If you try to start a cartel to do price fixing and only succeed in convincing two of your 50 competitors to participate, you've still engaged in illegal price fixing.
It doesn't matter if individual price negotiation happens or not. If a bunch of companies agree to set the same list price, but also agree that they can offer deals to their customers, they are still engaging in illegal price fixing.
It doesn't matter if the scheme actually succeeds in changing the prices. If two companies meet and agree to set prices at a certain value, but then they backstabber each other and undercut the agreed price, or simply other companies in the space who were not part of the scheme have too much market power to allow prices to change, the original companies still agreed to an illegal price fixing scheme and are guilty.
All of the above will probably have a massive impact on the amount of damages and so on. But they have no bearing on the verdict, as the FTC lays out at length in the filing they link from the article. And this is not speculation, it is established case law.