Recruiting for Summer 2014 Associate Class

I'm at a consulting firm where many of the second/third years exit to go into PE firms. I was wondering a few things:

1) When I should start reaching out to head hunters
2) When I should expect head hunters to reach out to me
3) When do PE firms begin to reach out and hold first round interviews
4) What is the interview structure for first rounds, second rounds, etc.
5) What types of hard/soft skills would the ideal candidate have?

I'm looking to recruit into a mid market firm ($4B-15B) or a bigger firm that is more consultant friendly, like Bain Cap. Also what firms out there are consultant-friendly, besides the following:

1) Bain Cap
2) Golden Gate
3) KKR Capstone
4) Francisco Partners
5) Audax
6) AEA Investors
7) Berkshire
8) Summit