Is it considered plagiarism if in the abstract, only key authors of frameworks used were cited and other peripheral concepts mentioned in the abstract were not cited but were cited in the body of the study?
In the abstract, you want to inform the reader about the paper that you have written, you want to convince the reader that is it worthy of their time to actually read some of it. You should realize that for the bulk of the readers, the abstract is all that they will ever read of your paper and as such, the abstract should stand alone, it should be a self-contained story. Including references in an abstract will ask for an additional investment of time from the potential reader, which might chase them off.
Plagiarism in an abstract arises when you copy text from other sources and include it in the abstract itself. In such cases, you present work written by others as something that you have done yourself, which is clearly wrong.
Plagiarism of another nature could arise when you imply that previous results from others were actually performed by you. As the authors of the original work will have an interest in your paper, rest assured that they will be the first to send you a message (if it was not picked up in the peer review process) asking you why you presented yourself as the author of work that you did not do.
Some final thoughts: - An abstract is supposed to be short, so there is no room for things that do not belong there (a thorough literature review is one of these things) - Clarity and honesty are essential. If you do not copy from other people and if you are Always clear (beyond a reasonable doubt) in your descriptions of the sources of the material that you present, you should be fine
I've worked on academic journals for 20+ years, and the vast majority (> 80%) don't allow citations in the abstract. Those that do require the entire reference (i.e., authors, title, journal, vol, pages) because the abstract has to be able to stand alone. If you cite "Smith et al." and the reader sees only the abstract, "Smith et al." has no meaning.
Regarding plagiarism, you don't need to cite specific works. Just use phrases like "in prior studies" or "researchers have reported XXX."
That is not plagiarism. Only when you don't cite the relevant source materials at all, plagiarism comes into play. Such materials ought to be cited next to the relevant concepts. You wouldn't have to cite the references every time you repeat the concept.
Having too many citations in the abstract is something to be generally avoided. As long as you cite those references next to the appropriate concepts in the body of the article, you won't be considered plagiarising content.