Oh, isn’t that exciting! For this recipe you will want the lid on – it helps keep in the moisture – and basically steams the chicken, making it nice and juicy when served. You can take the lid off near the end to let the skin brown and crisp a bit if you prefer.
Thank you for asking – I will update the recipe to note that. Enjoy! 

I just wash it & stick it in there whole.

Any kind of apple is fine. We used red delicious for this & sometimes Granny Smith.

Yes, the size will change the cooking time as well as factors like the efficiency of the oven, which is why I call for 1.5 – 2 hours & checking on the temp every 15 minutes beyond the 60-minute mark. I think a 5-pound chicken isn’t unreasonable & seems to be the average for what I tend to find at my stores.