The release of Kline wasn't surprising at all. The Patriots had ten total linemen on the roster after having claimed Braxston Cave and Chris Barker off of waivers yesterday. The Patriots typically don't keep more than eight or nine linemen on the 53-man roster. However, the team obviously likes Kline, so he's a top candidate for the practice squad should he clear waivers.
As for Cole, I was really surprised to see the Patriots release him in the first place. He may have been close to the bubble because of his place on the depth chart, but with his value on special teams, I thought he was safe. He wasn't exposed to waivers, so I suppose there was not much of a risk there. Not sure why the Patriots released him, but either way, he's back. I'd still expect him to land on the 46-man active game day roster.