Should I leave a blank leaf (two blank pages —is that called a flyleaf?) just before everything, when you open the book?
Can the so-called 'half title' page (a first page with only the title) show not only the title but only the subtitle if it is relevant?
Can the 'half title' page show the author's name?
Should I add a blank leaf (two blank pages) between the 'half title' page and the 'title' page (the page that contains all the relevant information: title, subtitle, author, city, publisher, date, etc.)?
The 'title' page will be followed by the 'legal page' (where copyright, ISBN info and things like that are shown), both belonging to the same leaf (I mean, the 'legal stuff page' will be placed on the verso of the 'title' page). Should I add a blank leaf (two blank pages) just after the 'title-legal' leaf?
And about typography... The typography used in the front cover of the book is the corporate one (the one that follows the corporate visual identity rules of my University and so on), which mainly uses Futura Condensed Bold, Futura Condensed, etc., but the main text of the book is typewritten using Palatino. So... Would it be a right solution using Futura Condensed for the 'half title' page and Palatino for the 'title' page? Other suggestions, please?
No, usually not. This is a legacy of hardbound binding; these extra pages were glued to the cover and the inner pages, and do not count as "inner" pages. For a paperback, you don't need to explicitly add them.
The page with the half-title is sort of a connector between the cover itself and the inner pages. Its use is (historically) to protect the real title page, as it would otherwise scuff against the cover. You are relatively free in its design, although mostly it is almost entirely blank, with just the title and, optionally, the author. I take it your main title is less informative than its subtitle, that is, you have something like "What to do next? Ten important tips on designing a book". In that case I would use both on the half-title page, with the title larger and the subtitle smaller. I've never seen, nor have been asked to use, only the subtitle here.
That is a matter of preference. Your name can appear one or two lines below the title (which should be near the top), or close to the bottom, or not at all.
No. Page 1 is the half-title; page 2 can be blank. Page 3 is your main title page, and page 4 contains the colophon. Page 5 can be a dedication (at the upper or lower right), in which case page 6 should be blank. If no dedication, page 5 usually contains the Table of contents. Do keep in mind that, since this is for a thesis, your university may have rules to follow for the front matter. For example, one of the universities I do typesetting for has very strict rules, where the colophon must be placed on page 2 and page 4 is reserved for the Promotion Committee details.
Now that, finally, is a pure design question ;-)
On the half-title, you may:
a. Have your title, subtitle, and name in the same font, orientation, and placement as on your cover (but in black-and-white);
b. Use some design elements from the cover, such as the font, but (especially if the cover design is, uh, radical) with a regular placement of the text;
c. Use the same font and style as in the rest of your thesis;
d. Combine all of the above.
It depends on the "role" of the half title: is it a step inbetween the cover and the 'actual' text, does it belong to "title matter", or does it belong to "the book".