I contacted WDW guest services about this last week. From what I was told the only thing closing is the Friendship Boat dock at Epcot. So, the only closure is the boats actually running from the resorts to the IG.
He assured me that the boats will still run from the resorts to HS, the IG would remain open, and that “walking would still be available”. He also implied that they would be offering bus service to the front entrance of Epcot to make up for the boats not running to the IG.