I noticed so many cases of Mavic power loses are attributed to loose battery. I am wondering if there is any products available to secure the battery and arms so that they wont move during extreme manouvre mid air, something that worked with clip on without blocking the sensors. Something like this.

As long as you double check that the battery is firmly secured before each flight you won't need to put a diaper on the MP.   

I am wondering if there is any products available to secure the battery and arms so that they wont move during extreme manouvre mid air

I'm not aware of any, but frankly I wouldn't recommend them if they did exist. For the battery you should just make sure you hear the "click" when you insert it and visually inspect it to make sure that it's fully seated.

And as far as the arms are concerned, here again your best bet is to carefully unfold them and inspect them before flight. The only way I'd expect one of them to get folded in mid-flight is if you collide with something, but if that happens you're likely to lose one or more propellers anyway and it probably won't matter whether the arms remain outstretched.