I am in favor of clear writing and against the academic attitude. All that said, I would still go ahead and write it like a normal journal article. Use the third person and the "we/our" for most of the results. After all, you will probably add at least your advisor to the co-author list of papers coming out (or have already done so if you already wrote the journal articles).
Just scanned my thesis, which was mostly stitched together chemistry papers. Not like a European one where all it is, is the papers themselves. But pretty clearly taking different papers and with some minor edits changing them into chapters (e.g. combining redundant methods). I was pretty much either talking about the chemicals or using the passive voice or saying "our" for discussion of interpretation and such. But these were sections where I had co-authors, professor at least.
I did have one minor area (other than acknowledgements) where I used first person and got no static for it. Within the Intro, after giving a review of previous work, I discussed the research objectives (in a one para section called that) and used "my" in context of "my goals changed during the student. Initial my goal was X; subsequently it was Y. Didn't get any static for this--it was a helpful para to explain why the chapters to follow in the thesis were connected.
There are a lot of other areas where you can cut the crap and be honest (for example, I shared some important lab safety learnings and equipment construction that was helpful to subsequent students but really fit in a thesis more than a results journal article. I did that on purpose because the main audience was/is future group members.
But I wouldn't make a big deal of the impersonal style. Some of it is good (keeping attention on the chemical, not the researcher). Some of it is bad (pompousness, or not taking responsibility). But overall, it's not worth worrying about.
Get the union card done. Thesis is pass-fail and very little read. Don't mess with it too much, just wrap something up, get a job and boogie. Defense committees can be very accommodating as long as you have published well (already showing ability to make solid contributions) and have gotten someone to hire you!