I am at an Australian university studying Ph.D. I have written five first-authored papers related to my thesis topic during my Ph.D. candidature. 3 of them are published. 2 of them are under review now. One of the published ones is only a co-first authored paper. There are 3 co-first authors on that paper.
I am unsure whether I could paste most of the content of this paper into the thesis. As far as I know, most of my Ph.D. fellows would do this if they were the first author. I consulted with the university's academic intuition and they told me it was fine as long as I cited this paper at the beginning of the chapter. The other two first authors also agree that I contribute most to this paper.
But I am still unsure. If I am not the sole first author and copied the material, would the thesis examiner outside my university consider this behavior plagiarism? If this is too risky, I would rather not include this paper as a part of my thesis. Re-phrasing the whole paper is too time-consuming for me. But not including this work would influence the completeness of my thesis.
The academic consulter at the university told me that I should isolate my contribution from the others in the paper and only write down my contribution. But the idea of the whole paper is mine. The other two first authors are basically only executioners, so I have no idea how to isolate them...