the overarching goal of scientific research should be to eventually completely replace animal models with non-feeling alternatives, to remove this ethical dilemma completely.

You touch on so much here. However, I would like to just make a few points:

In the U. S.
"The following animals are not covered: farm animals used for food or fiber (fur, hide, etc.); coldblooded species (amphibians and reptiles); horses not used for research purposes; fish; invertebrates (crustaceans, insects, etc.); or birds, rats of the genus Rattus, and mice of the genus Mus that are bred for use in research. Birds (other than those bred for research) are covered under the AWA but the regulatory standards have not yet been established.

In other words, for the sake of the animal research industry, many animals are defined as not animals, although these non-animals represent the vast majority of non-human research subjects. "By some estimates, as many as 95% of all animals used in research are now expressly exempt under the principal federal law charged with ensuring laboratory animal welfare".

Given the high cost to the research subjects (animals), it is interesting that many in the research community question the reliability of animal studies: "many investigators are increasingly concerned that animal experimentation may be based on a scientifically flawed premise and that it retains its acceptability only because clear alternatives have not been identified. Dramatically rising costs and extremely high failure rates in drug development have led many to re-evaluate the value of animal studies".

And

"A 2006 review of 76 animal studies, for example, found that approximately 20% were contradicted in humans and only 37% were ever replicated in humans (10). A review of 221 animal experiments found agreement in human studies just 50% of the time—essentially randomly"

I'll stop now, because I recognize my response may seem extreme. I don't think it is. It is the result of reading and research I've carried out over several years. In addition to the points I have briefly made here, please consider how many animals are sacrificed because a high school student needs to dissect something, or a university student needs to practice on something. There is a total disregard (in my experience) for the value of animals' lives in educational institutions.

Finally, please think about the erosion of empathy and sympathy that must take place in people conducting these experiments. This, too is a cost. These people return to their homes, their families having cultivated the ability to look away from suffering. I'm not sure that's a good thing.

Thank you for this very reasonable article. You raise many questions that require serious thought. I sense you are on the side of the animals :) I hope so.