I have seen several people take 8 or 9 months of parental leave. I heard a couple are doing a year right now. I personally took 4 months and will take more next time. Most people get kinda restless sitting at home after a few months, so I expect the average to go up but not to a year.
I can't speak for the design team, unfortunately, but they never look unhappy when I walk by :) the space they have is awesome, it's set up for collaboration in a free cool ways.