Hi prizmbatch and welcome to the discussion forums! Congratulations on your new plants. The combination of tropical pitcher plant, VFT, and cobra lily sounds suspiciously like a Lowes purchase - a plastic cube perhaps?
All three plants have different growing requirements. The Nep (probably a N. ventricosa) is an easy plant to grow. Since I cannot be sure what it is, your best bet is to keep it in a container, like a terrarium, to provide higher humidity. As was suggested earlier, a VFT does fine uncovered, but sitting in another container that has 1/2" of grocery store distilled water, at a window sill. The cobra lily is a more difficult plant, but for now, keep it in the same conditions as the VFT. Right now I would concern myself with either keeping out of or preventing them from being in shock. Store bought plants are ofetn neglected and taking them home could put them over the edge. Dead leaves is a good indicator of possible neglect.
Could you describe the soil that they are in, like how moist it was or how green or brown the leaves were when you purchased them? Any chance of posting pictures? Need help with that? We can help.