1. Yeah, carbon lasts for maybe 4 weeks at most, so it's definitely expired now. Besides, I read that the plants take up the nutrients faster than the carbon traps them so even if it was still active I don't think it would matter.
2. For plants, there are three main types: low light (15-35 PAR), medium light (35-55 PAR), and high light (55 and above). Low light plants are best for beginners, so if you want to go low light I would recommend something around 25-30 PAR. If you're willing to go for medium or high light plants, it will generally take more time, money, and effort, but is generally better in the end. So, first, decide which light level you want, and then it will be easier to recommend lights and equipment.
Also, PAR is a way of measuring the intensity of a light, or, more precisely, how well plants can use it (I think). Anyway, in general, the higher PAR, the more light available to plants.