I really hold back on the salt in this dish. If you would rather, taste the cheese sauce before you add the cauliflower to it, and re-season if you'd like.
If you want some heat, feel free to add cayenne pepper when you add the garlic powder, I've even been nutty enough to add turmeric at the same time, cuz turmeric is so good for you. It will alter the flavour slightly, so be warned. The kids may notice.