Santa and Niklaus were coming to town Christmas 2010. Each one tried to hand out more surprise presents on the battlefield, turning it to a winter mine field. They returned Christmas 2011 and 2012 as expected.
Bundle was released during the Winter 2010. The hats were released already one year earlier and came back in these bundle only. That's why there were also bundles without hats for the people who had them already.
For Charity BF:Heroes would be donating 1 $ per Santa or Nikolaus bundle sold (approximately 10% of the bundle value). If more than 8000$ was reached, another 8000$ would be put on top!