aluminium foil versus baking paper for making chicken?

You really need to give more information. As a chef, I never want to put foil directly on meat. By sealing the meat/vegetable package, you will actually be steaming the meal. As this is the desired method for low, slow cooking, it also has to be removable to brown the chicken before serving or you will be serving a white bird. Since you want to roast your chicken I would recommend the low and slow method of cooking chicken with baking paper and foil over the chicken and vegetables with your seasoning. top with baking paper and seal with foil. Do not add water. By adding water, your meat will become stringy. when the meat and vegetables are ready for the oven, place in a 300 degree oven until everything is cooked through. It should take about 2 or 3 hours depending on the size of your chicken. When it is cooked, remove the foil and paper, scoop out the vegetables to a plate and keep warm, drain pan drippings into a pot to make gravy. Increase the oven temperature to 400 degrees. Return the chicken to the oven, breast side up, to brown, while you thicken the pan drippings to make the gravy. Adjust the seasonings as needed with salt and pepper, but nothing else should be needed.

Hope your dinner is amazing!

You don't need the baking paper if you have the foil the foil will help maintain a level of moisture, ad the paper might tear and stick to the chicken, the foil is nonstick the paper tends to smoke sometimes, foil is your best option right now.

You could always line the pan to prevent stains but place the chicken on a rack, and roast it ill be the same and won't soak up all the fats

The best way to do this is to use both. You cut some pan liner(baking paper) to be just a bit smaller than the foil. You put the two together then assemble your food then wrap paper and seal the foil as a package. This is how the pros do it.

If I were you, I would just put your thin layer of butter or vegetable oil right onto the metal tray and bake your cookies that way. The foil will probably just end up burning your delicious cookies!

I only use foil.