Does a positive thinking necessarily bring positive action, habits, and results?

Exactly, very true to be said, depends on our attitude if we have a positive attitude the outcome is also positive.

Yes it does! Positive thinking can actually lighten everything. It helps you be more motivated to work harder. 

No.

It does tend to be helpful though.

Note that excessive positive thinking can become denial of negative feelings, which is unhelpful in the long term.

yes, true a positive thinking brings positive result.