Without denying there being a legitimate role for philosophy, I think that the prospect of many ostensibly moral issues eventually turning out to be scientific issues makes sense, given a proper understanding of what “science” is. Philosophy might tell us, for example, that the ultimate choice before us is life or death; but science might tell us what means are appropriate to implementing the choice of life, in more more detail and much more conclusively than is possible for an ethics founded on common observations of human life. After all, science has given us much improved prescriptions for medicine, for engineering, and even for economics (though governments are not much inclined to follow them); common sense rules for bringing down a fever or building a bridge that will stand up, which is what the Romans had, were useful, but not as good as twenty-first century methods. And ethics is also an applied branch of knowledge.

“Should I buy a red hat or a blue one?”
“Do I prefer Rachmaninoff or Tchaikovsky?”

These are personal (though still objective) – and not universal like scientific data.

First all the examples I considered in the post were of the form “Should I do …?” By the definition of morality - morality refers to making choices in light of free will and the fact that life offers fundamental alternatives – these are all moral questions.
The answer to these questions might involve matters of political science or physics or economics. In the example you gave – the question “should we implement a 4-year term limit on presidents” is both moral and scientific – it is political science that is relevant. So yes, it is indeed both moral and scientific.

As a specific example consider the question “Should I support the government bailouts?” The question is both moral and scientific and comes under politics. What I am claiming is that because I have accepted the principle that theft does not work irrespective of scale or circumstances, the question seems to me to be purely moral. When I first came to know of the proposed bailouts, my rejection of the idea was immediate and purely based on moral grounds. I did not feel the need for a detailed cost-benefit analysis. To a pragmatist however, the answer is not at all obvious and a purely moral argument is insufficient to convince him.
Now consider some of the questions Monica raises in this comment on patent laws and genetics. To me (no expert in either IPR or genetics), the questions dont seem decidable on moral grounds. To a lawyer who has some experience in the fields however, some of the questions might well have obvious answers. Since he has integrated the relevant principles in his understanding, no scientific evaluation is needed, and the question might seem purely moral.
This is the distinction that I intended to analyze and to me it seems both valid and useful. Are you saying that it is not?

The key difference between these examples is emphatically not whether or not you have principles to help you answer them. The difference is in the category of knowledge to which the principles belong. Knowledge is classified depending on the types of entities, actions, entities, etc. to which it refers. Metaphysics refers to the nature of all entities and actions in the most general terms, epistemology refers to man and his means of gaining knowledge, morality refers to making choices in light of free will and the fact that life offers fundamental alternatives, and politics refers to the nature of social interactions among men in light of morality and the facts of man’s nature. All of these together (along with aesthetics) are classified as being part of the wider class of knowledge, philosophy, which “studies the fundamental nature of existence, of man, and of man’s relationship to existence” according to the Ayn Rand Lexicon.

In contrast to philosophy is science, which studies particular aspects of existence (the physical sciences) and of man and his relationship to existence (the humanities). In the physical sciences, physics studies the fundamental interactions between all forms of matter, chemistry studies the nature of elements, molecules, compounds, etc., mathematics studies the nature of relating physical measurements to one another. In the humanities, history studies the forces underlying the flow of past human events, economics studies the nature of wealth creation, and political science studies the effects of given social systems and, conversely, the social systems that lead to a given effect.

So with respect to the particular topic put forth in this post, a distinction must be made between politics, which is a subset of morality, and political science, which is not. In essence, politics answers the question: “which social system should man have?” while political science answers the questions: “how do different social systems act and what social measures can lead to a particular goal?”. To put it another way (though this oversimplifies): politics defines the goal, political science defines the means to achieve the goal.