I think this is more of formatting issue than a foreign language issue. In any case, you're stuck with me since I'm the moderator of both Formats and Foreign Language. In foreign language we generally follow Formats, except where something specific to foreign language makes it necessary to do something else. There are no foreign language exceptions that apply here, so this is just about Formats.
Unita must be centered as you did in your "b" braille file. Unit headings are specifically required to be centered in Contents. So that takes care of that.
Titolo (Title) CANNOT be used as an identifier because an identifier is used ONLY in connection with numbered main entries. So even though Titolo is [u]repeated [/u]in each main entry, it is not [u]numbered[/u], so you just don't have an identifier here.
Thank you so much for sending the print and the braille samples. That is very helpful.