Well, Pd isn't necessarily design with that sort of interface in mind, say like a tabbed interface like tabs in your web browser. Pd has these things called "subpatches" where it's basically you double click on a box in your main view (called a "canvas") and it opens up a new window. There's not something like dropdown menus in the default distribution of Pd (called vanilla Pd) but there are toggle boxes, rows of buttons called "radios" (like the HTML radio selectors) and sliders. You can also call up windows that look like your usual "Open" and "Save As". And for your samples, audio data (and pretty much any sort of numeric data) can be stored in graphical arrays that you can click and mess up at will, so I think that pretty much checks all your boxes. There's also text editor windows like say,.. if you open up Notepad in Windows or Mac. Can't change font but you can edit lines of text and save it. There's also these graphical things called "data structures" but perhaps those are a bit more on the advanced sid of things... So you have many option to achieve your goals and I think you could get your ideas done granted you're a little flexible on how they get done.
