How the libxcb1-dev package can be available in step 1 when you installed it in step 3? Did you check what is in file outputConfigure.txt? First of all it said that configuring failed so builind Qt then was pointless. Then it said:
Qt Code: 
  1. The test for linking against libxcb failed!
  2.  You might need to install dependency packages for libxcb.
  3.  See src/plugins/platforms/xcb/README.
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Did you checked this file?

And remember to install packages first on the RPi and then copy the sdcard to your sysroot dir, because they are needed in the compile time.