There is nothing wrong with butter - repeat after me.... There is nothing wrong with butter!!!
Margarine is what is unhealthy.

For sugar substitute I use erythritol and/or stevia. Both are 100 per cent natural. You can buy Natvia or Norbu from the supermarket (although I buy erythritol in bulk from iherb in the US). I don't use fruit to sweeten because I don't eat fructose (except the occasional handful of berries). But, apple and banana are good alternative sweeteners.

Oil is fine too. Just not seed oil. So no vegetable, canola, sunflower oils. Use olive oil or coconut oil for baking. Or butter!