Ok, so very important, air beds are actually REALLY not a great idea for camping, you effectively have to heat all the air with your body before you’ll be warm (which you cannot do when it’s 5 degrees outside). Much better bet is a Thermarest type pad, if you’re committed to air beds, bring a patch kit & several extra blankets to put between you and the mattress.
Also make sure you & dc have non cotton PJs, and preferably mostly non cotton clothing as when it gets wet, which it will, it will not dry, and you’ll freeze. Figure you need to dress for the minimum temperature all the time as since you wont be able to go indoors much, you will get cold & cold will settle on you.
I would also advice against budget gear, you get what you pay for. Pay attention to sleeping bags temp ratings, you want the “comfort” rating to be well above the minimum temp you’re expecting overnight. If the bag you bought doesn’t have a temp rating, it’s highly unlikely to be adequate.
Bring lots of hot chocolate mix & marshmallows for everyone.
Get everyone camping chairs.
I just took toddler DC camping on my own & had a great time, were warm dry & fed BUT I spent upwards of 50 nights a year camping for about a decade and my camping gear collectively cost well over £3k over the years to get properly equipped.