Yes i believe you can - you can make a zero points smoothie as long as you dont add any dairy to it. However you have to point ready made smoothies like Innocent, even if they say they only contain fruit, and they're quite high!
i suppose they are figuring that you are burning up lots of energy making them yourselves
As far as i'm aware you can make your own yes. Theres a smoothie in the books that is only 2pp, and the 2pp is for the natural yoghurt in it, so they must be free x
You can Yes. Only the yoghurt you use is pointed. I usually make mine with an activia fat free yoghurt (2pp), strawberries, banana and blueberries and some water. My leader did say thou you have to drink it more or less as soon as you make it as it ferments if you let it sit!
Yep they are free. You can get bags of value frozen fruit from tesco and I just let them thaw because I don't like lumps and add water as I hate yogurt or anything that's the same texture... (makes me gag!) and hey presto!! Gorgeous and yummy and cheap!!!