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
Five steps is not a Buddhist belief.
Nirvana.
buddhists, funnily enough
Yes.
Most Japanese are Shinto and Buddhist.
There are 31 planes of existence in Buddhist belief
Not at all, that's why it is called your "Belief" my friend.
In some aspects, yes.