I think it happened and fell in line with the prophecy, but was not solely because of the prophecy.
W&H made a choice to bring her back as a bargaining chip/weapon to use against Angel in S2. It…worked? Somewhat? But it feels clear to me that their intention was never directed at getting Angel to have a child with her. They simply thought she was a weakness for him.
If the goal was to create Connor as part of the prophecy, W&H did a really bad job of it. They tried to kill him several times over in S1 & even a few in S2. They should’ve done more to “help” him and align theirselves with him if that was the end goal. Otherwise, why make him an enemy?
And as for Darla, they did a horrible job of controlling her. She and Dru went on a homicidal rampage ASAP and killed a number of individuals, including the high-ranking Holland. I doubt that was in the plan.