1. Semantics is generally considered a branch of linguistics. Philosophers like Russell have made major contributions to semantics in the form of semantic theories for a variegated class of expressions, such as descriptions.
By the "semantics of descriptions", I am referring (1) to the specific issue of how descriptions (as propositional particles) refer to the external world, which is a special case of how language (as propositions) refers to reality, which is what the philosophy of language is all about; and (2) to the problem of how to model descriptions in modal contexts, which, in the case of Russell's treatment of proper names, upended his theory, thanks to Marcus and Kripke. David Lewis also contributed to this area, with his counterpart alternative to Kripke's possible worlds semantics. All of this stuff is philosophy of language. And I believe your own citations support that. Of course, semantics as the study of how natural languages acquire and sustain meaning in the context of usage by people who write and speak human languages, is a branch of linguistics. No argument there. Note that linguists did not participate in any of the above. Because Russell was not working in linguistics.
I've cited a popular linguistics textbook recognizing the contributions of Russell to semantics -- the book also asserts that semantics is a branch of linguistics, an uncontroversial claim -- thereby meeting your challenge to cite a single linguist (I cited a triplet) recognizing Russell as a contributor. I've pointed you toward hundreds of scholarly citations of Russell's work by linguists. I can direct you to recent linguistic work in semantics adjudicating between Fregean and Russellian theories of the semantics of descriptions, thereby affirming these theories' continued relevance to the field. (p.131) That I can do all of these things is highly suggestive of the fact that Russell in fact contributed to linguistics, whatever journal he originally published in. You haven't presented evidence to the contrary.
You have indeed cited a source, although I believe the source discusses Russell's contributions to the philosophy of language, which in some academic departments (specifically where one of your referenced textbook's authors teaches and at MIT, where Paul Elbourne got his Phd) is taught in the same department as is linguistics. (In the case of MIT, the unification of the graduate programs in linguistics and philosophy was done for budgetary reasons; Chomsky, then chairman of the MIT department of linguistics, agreed to absorb the costs of the philosophy department at a time when it was on financial life support, and for no other reason.)
I do think that linguists reference philosophy of language quite a lot, just in the sense I mentioned. That does not make philosophers of language contributors to linguistics. I will grant, as I did implicitly in referring to what has transpired historically and what is true now, that in Russell's time there was a lot of overlap between the fields. But today, if one were to decide between whether to go to graduate school in linguistics or philosophy, the advice on all sides would be to pick linguistics if one's goal is to contribute to modern linguistics. But there are joint departments, and if you are saying that there is overlap, especially in the study of formal languages that Chomsky's generative grammar theories motivate for linguistics, I would have to agree. But that is like saying that because experimental psychologists use Bayes' theorem, and reference it all the time, that Bayes contributed to psychology. I took your citation of Russell's work to
not be an argument of that sort, since you were, I believe, adducing support for your view that philosophers contribute to science. So I took "contribute" in the more substantive sense. If all you mean is that the philosophy of language is of interest to linguistics, which regularly cites it and its practitioners in advancing linguistic theory, then I would have to grant you that.
The same argument applies to all the other philosophers who I would assert have contributed to linguistics, e.g., Grice and Austin in pragmatics (another branch of linguistics).
The same point again concerning these two, as was made regarding Russell.
2. Regarding citations: you're right, the fact that Russell's work is so widely cited by linguists doesn't by itself make it a work in linguistics. The fact that it is a work in semantics, a branch of linguistics, does. Independent of the label we apply to it, it is clearly a contribution to the scientific study of language, as evinced by (1).
You can just Google Russell in the discussed context. The semantics of descriptions is a topic in the philosophy of language. Although Wittgenstein did discuss the semantics of natural languages quite a bit. Note that in the "Tractatus" he discusses semantics in the philosophical sense, and in "Philosophical Investigations" he does so with respect to its sense in linguistics.
3. Kripke attacked Russell's theory of descriptions as applied to names, and even then he recognized it would be true of names at least some of the time (see his discussion of 'Jack the Ripper'). He and the other philosophers you mention discuss names, whereas I am discussing Russell's semantic theory of descriptions more generally. Or did Lewis have some theory of descriptions I'm not aware of?
You miss his point. That Russell's treatment of proper names is only true some of the time is the problem with it, and Kripke's possible worlds semantics for modal logic ("semantics" in the philosophical sense) shows this to be the case. Lewis provided an alternative semantics with his counterpart theory.
Well, you're free to ask them whether, e.g., Modularity of Mind counts as a contribution to cognitive science or not.
The problem with Fodor is his non-physicalism, as stated. Scientists these days are materialists, at least with respect to their specific fields, whatever their beliefs generally.
We agree on this matter.
Given that we agree on that, would you then say that philosophy also has made contributions to physics? Not counting when physics was called "natural philosophy", as it was in Newton's day. Would you say that Albert Einstein, because he wrote quite a bit on philosophical topics, was a contributor to modern philosophy? I would say No to all of that, as would most scientists (especially physicists), but I do think some philosophers would disagree. However, I'm with Wittgenstein, Hawking, and Weinberg in their view that philosophers generally play language games and have abdicated their historical role in understanding reality to science, to which they now make no material contributions of any kind.