I think that an ETF will have little short term influence on the price of bitcoin, long term it might increase the price through greater reach to the market. I don't think that any ETF will be approved in 2018, I wouldn't be surprised if it takes until 2020, always with these things there need to be constant iterations until the SEC is finally happy with what's being proposed.
There is a high chance that bakkt will get approved specially because it has very big names in it, and the proposal makes alot of sense