I don't see these contracts affecting the price in anyway. Everyone was expecting a price increase when CME and CBOE decided to introduce futures trading and when it happened, the price wasn't affected. I wouldn't put much hopes on it.
^^This, plus the fact that the futures are cash settled. This means that when they expire, no actual bitcoin is transferred to/from anyone, and therefore, the contract expiration does not directly affect the price of bitcoin.
They will affect the price by the actions of the participants in that market. Overall it should be a positive as it allows various finance firms to hedge involvement with crypto without exposing themselves overall to the underlying risk of holding a crypto token like BTC.
So its increasing business participation and allows reduction in arbitrage risk while involved. It also allows speculators to take a naked short but then later source the bitcoin via various means in order to counter that naked short.
So the closing of each contract could be significant as its marks the ending of each round between bulls and bears. Heres my current take, I do think BTC itself is important, people even but finance can tip the scales also and they have ways to engage available sources of btc I think. Just offhand I remember people complaining about JP Morgan shorting Silver, however they also took up an interest in a silver mine so they were hedged. I expect CME CBOE would also relate to similar activity in actual crypto; I know dont the details of the links however