I've found the heat from the CHE will heat up the lid and the air in the enclosure with no issue. As far as air holes, I've always used a wire clothes hanger. Cut the bottom of it with a pair of tin snips or wire cutters, and then just heat it up with a candle or something similar, obviously exercise a lot of caution here as everything will be hot, then just push through the sides or top to create your holes. This works a lot better than a screw driver because your pressure point, the end of the wire hanger, is much smaller and doesn't require as much heat or force to penetrate the plastic.
Just be careful, it's easy to hurt yourself.
Edit to add: Just to be clear, and I know I may not need to say it but just to say I did, as with any other enclosure, that Q set up with a tub runs for a week or so before anything goes in it. Still needs a thermostat and thermometer and hydrometer, same process as setting up a new PVC or glass enclosure.