Heh well I managed to kick Rome's tail with Libyan Spearmen, Carthaginian Citizen Cavalry, and local merc backup. Works quite well. So my answer would be to not even bother with making the heavier units until you feel it is right. If you're RPing the Punic Wars, just wait until you declare Punic War I done with and go with that. Though I think that the Elite Africans were already around but in small amounts. So make 1 or 2 of each and try to avoid retraining it for the course of the war. The Liby-Phoenician Heavies and the Iberian Assaults I'd wait until Punic War II or Hannibal-era general for them. The Libyan Heavies I think you could make and not worry as it wasn't so much a counter to specific Roman developments but a natural progression of the concept, though it wouldn't be necessarily bad to wait until after your first War for them as well.
Since you didn't mention the Sacred Band units I presume you already have a plan for them? If not I would follow the Elite approach and only make 1-2 of each as well and try to avoid retraining.