Buddhist beliefs are summed in the Four Noble Truths. All the rest is commentary:
Phil Mickelson is not a Buddhist. His bio doesn't specify his belief system.
Buddhist is their main belief
five steps
http://buddhism.kalachakranet.org/karma.html
Buddhism does not believe in a Supreme Creator.
Five steps is not a Buddhist belief.
Nirvana.
buddhists, funnily enough
There are 31 planes of existence in Buddhist belief
Most Japanese are Shinto and Buddhist.
Yes.
In some aspects, yes.