Ok, took a look at the preview. The key problem is, of course, that you cannot teach everything in one semester. The book starts in an absolutely correct way stating clearly what assumptions they make and what viewpoint they will explore in some reasonable depth. It is inevitable for any one-semester presentation even in such "uncontroversial" subjects as mathematics to be lopsided: you decide what highest points you want to achieve and essentially just combine the shortest routes to there allowing yourself some leeway for improvising occasional funny deviations when you feel like it. It is just the words "This is what the economics is about" instead of "this is the point of view that we will accept throughout this course to keep the exposition uniform and the conclusions consistent" that irritate one (especially if repeated more than once).
So, what I would suggest is to start with finding the depth-width compromise you want to make, to select sufficiently many points of views that you can explore in sufficient depth. Then, once you figured that out, choose the topics you want to present from these points of views and run some comparisons. That is a huge headache if you want to do it right and the goal is to give a clear picture of several approaches and their comparisons and interplay instead of just totally confusing the students so that the only thing they have in their head in the end is "everything is relative and you can come to any conclusion from any assumptions if you accept a convenient point of view" (I cannot really create such mess in mathematics, but I can easily make it if I ever give lectures on problem solving techniques, so I suspect your case is somewhere in between).
From what you said, it also looks like there will not be any single textbook you'll be able to use, so my advice would be just to lay all books aside and to plan the whole course without consulting any (I occasionally do it for graduate courses and for terminal undergraduate courses like "history of math" where I'm not bound by some particular curriculum requirements). Then you have two options.
The first one is just to declare a "no textbook course". The students usually squeak rather loudly when you do it (in the USA, at least; in Europe it is a more widespread practice) but if you have tenure, it shouldn't bother you too much. If you do it and you really care, you'll have to make at least some handouts emphasizing the main points, keep longer office hours, etc. I've done it several times with undergrads (I'm teaching math) and it worked more often than not, but it is again a headache.
The second one is to search for 2/3 textbooks and to assign all of them clearly stating in the syllabus what will be covered in each one and in what order. I have never done it (I hate to force the students to pay 3 times the usual price and I cannot legally just tell them to download everything from you-know-where) but it is still an option.
In any case, the point is that fostering pluralism in one course by one person comes at an enormous cost. If you are willing to pay it, by all means go ahead, but remember that the more traditional way of fostering it by spreading various points of view over different courses taught by different people works not too bad either ;-)
:-). Cf. cseducators.stackexchange.com and matheducators.stackexchange.com