How can two planes be on the same taxiway facing opposite to each other?
The taxiway is being used for parking. Specifically, parking of two MD-80s that have attracted press attention—The Australian: Clive Palmer’s $10m in tax-haven jets sitting idle:


  TWO 155-seat jets owned by Clive Palmer and branded with the name of
  his controversial and longtime loss-making company Mineralogy sit
  mothballed in a remot­e corner of Brisbane airport.
  
  The McDonnell Douglas MD-82 jets, worth roughly $5 million each, are
  registered in the Cayman Islands tax haven and have sat mothballed for
  months, possibly years.
  
  ...
  
  A spokeswoman from Brisbane airport confirmed the planes were owned by Mr Palmer and had sat idle for “at least several months”, but was unable to confirm exactly how long. “The space is leased from Brisbane airport and the owner pays leasing fees to have them there,” she said.


That article from 2014 shows them parked head-to-tail, but presumably they've been moved since then (the Google maps imagery is from 2017). 

If you're wondering how I found this, I zoomed in on the satellite image and used 3D mode to get a better view of the side of the aircraft well enough to sort of make out the "Mineralogy" label on the side, and Googled from there.