In the sample essay outline, could I use the outline including its thesis and conclusion as my own without out it being consider plagiarism?
I hate to be the bearer of bad news or to contradict the previous poster, but even if every word is your own, you may still be plagiarizing if you too closely copy someone else's argument without giving them credit. Plagiarism covers more than just using someone else's words without giving them credit; it also covers using their ideas.
The best course of action, I believe, would be either 1) to develop your own argument from scratch, especially your own thesis statement, or 2) to acknowledge that you acknowledge somewhere (maybe in a note at the end of your essay or in a conversation with your teacher) that you've taken the ideas for the thesis statement and conclusion from an outside source.
If every word is your own, you will be fine. Make sure that you use the outlines for inspiration, do not copy them exactly. Use your own words, and make sure your own understanding of the text comes through.