No, timeanddate.com is an independent entity which sources its primary information in the same manner we do.  They are not a primary source for our purposes.  Further, the change has already been made in the development version: https://github.com/eggert/tz/commit/efda0562d7fc7bc90b6cab76998fab8b4953e056

As Paul mentioned before, he is a volunteer, and there is no set timetable for full releases.  https://mm.icann.org/pipermail/tz/2018-October/026937.html

In particular, we are also waiting for a change in Volgograd, Russia to become official: https://mm.icann.org/pipermail/tz/2018-September/026898.html

If you need updated data files for Brazil faster, source files for the bleeding-edge development version are available from https://github.com/eggert/tz in the meantime.  Otherwise, please be patient.  A lot of last-minute changes tend to happen at this time of year, so it is advantageous to batch them together when possible.