Hi,
I can only answers your number 2 question;
On A300600, last airbus that I flew, Brake Fans must be OFF prior to takeoff, and the Max Allowable brake temp. for take off is 300 degrees C. Having said that:
1. If prior to takeoff with Brake Fans ON, the brakes temp. exceeds 150 degrees, it is likely that the brakes temp. will exceed 300 degrees during Take Off roll as the Brake Fans is switched off.
2. If with Brake Fans OFF, the brakes temp. exceeds 300 degrees, take off is not allowed as the max allowable brakes temp. is 300 degrees, if exceeded, fuse melt could occur in the event of rejected take off.
Hope it helps.
As for your winglets Q, I am not good at aerodynamics, all I know they are there to reduce induced drag (i.e drag generated as a result of lift). But no idea as to why different shape.
SS