Your sources can be current, but they do not have to be. In BIOL 1110 you had to choose an article published within the last 12 months, but this is not required for this assignment. So long as your 10 sources meet all stated assignment criteria, the research can be from any year of publication.
“In-text citations” may be (Name, YEAR) citations, or footnotes or endnotes. You’re looking for evidence that you can track specific statements the author is making throughout the document back to the original sources. The exact style being used isn’t important; what’s important is that the information is being cited.
Yes, “expert” is a kind of fuzzy term. Is someone an expert if you’re reading their first peer reviewed publication? If they’re writing about Biology but are normally Philosophy faculty? Don’t get stuck on defining and debating the term; use the definition being used IN THIS COURSE, FOR THIS ASSIGNMENT: “someone who was either paid to do the research or has published peer reviewed material based on the research.” If you think you have evidence of this, and can explain or defend your decision to use the evidence, then you’ve done your work – there isn’t going to be one right answer.
Note that the CSE Style Guide says that you are to include both a URL and a DOI for electronic articles. You can do this if you wish, but for this assignment, your instructors are fine with you bending the rules a little: you can just provide the properly-cited article details. The only time you will need to provide a URL is if you're citing an actual standalone website.