(a) it contains a list of all references (sources of information), presented in accordance with the layout style guideline;
(b) reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose);[2]
As below, you could make a more coherent narrative using only text rather than bury details in confusing lists.
Pass
(b) (MoS)
Your list of candidates passes MOS:LIST but I find it needless. This wasn't a real primary and you discuss the potential contenders well enough in the prose. I'm not going to impose my preference, of course.
My one qualm (but not an issue for GA) is that this exclusively relies on primary sources. I might question if the subject is notable since it's all local coverage.
Pass
(b) (citations to reliable sources)
Newspapers pass as coverage. It would be better if we had a history book about this election.
Pass
(c) (original research)
The article says what the sources support. You could have mentioned that not only did Young become the longest-serving GOP member of the House, he later became the longest serving in all of Congress. You cited a source which said so (Politico) but you didn't add that claim.
Pass
(d) (copyvio and plagiarism)
COPYVIO detector says it's fine. I don't see any close paraphrasing of sources that concerns me.
Pass
Broad in its coverage:
Criteria
Notes
Result
(a) (major aspects)
There isn't an aspect of this that wasn't covered. The only thing you could have mentioned were the other men in the plane crash but that's not the focus of this article.
Pass
(b) (focused)
Seems straightforward to me.
Pass
Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each.
Notes
Result
No bias read.
Pass
Stable: it does not change significantly from day to day because of an ongoing edit war or content dispute.
Notes
Result
No heavy editing volume here.
Pass
Illustrated, if possible, by media such as images, video, or audio:
Criteria
Notes
Result
(a) (images are tagged and non-free images have fair use rationales)
All the images are public domain or claim to be mere graphics un-copyright-able; it seems good enough.
Pass
(b) (appropriate use with suitable captions)
The same simplistic words mentioned above don't really need explanation.
Again, with nothing but local coverage I wouldn't seek an FA review but I think it passes GA. I'm very glad you may such good use of snippets from newspapers. It made my job of verifying much easier.
^ Compliance with other aspects of the Manual of Style, or the Manual of Style mainpage or subpages of the guides listed, is not required for good articles.
^This requirement is significantly weaker than the "comprehensiveness" required of featured articles; it allows shorter articles, articles that do not cover every major fact or detail, and overviews of large topics.
^Vandalism reversions, proposals to split or merge content, good faith improvements to the page (such as copy editing), and changes based on reviewers' suggestions do not apply. Nominations for articles that are unstable because of unconstructive editing should be placed on hold.
^Other media, such as video and sound clips, are also covered by this criterion.
^The presence of images is not, in itself, a requirement. However, if images (or other media) with acceptable copyright status are appropriate and readily available, then some such images should be provided.
Pass