You mention underlining in d'etudiants. You also mentioned Formats 5.81a which says to use italics for emphasized letters. That means you CAN'T use underlining there; the terminations sign used with italics within a word is unspaced. See the example the immediately follows. The apostrophe here is actually part of the word, so the termination sign follows the apostrophe and the rest of the word follows that, inspaced.
In EXAMPLES list at the top of the page, use italics for the bold and drop the italics from all the words that are not bold in print.
In the EXCEPTION 1 translated sentences, drop all the italics and just use italics for the underlined words, again because of the d'. This is a awkward situation because d' is actually a whole word, not just a letter. It is really de (as in de problemes in the first sentences above it) and the e is dropped because the next words begins with a vowel. However, for clarity, I would treat it as an individual letter within a word because the language usage requires it to be joined to the following word. In the explanatory sentence under EXCEPTIION 1, retain the fonts attributes as printed. In @2, just use italics and for the translated phrases just use italics for the underlining and drop all the other attributes.
For item #3 explanatory sentences use JUST bold for the French words only. Itslics not needed for the English in parentheses because the parentheses sets off the English as a translation from the preceding French. In the examples sentences at the bottom of the page, drop all the italics and just use bold as printed.
I know this looks confusing and even contradictory, but font attributes are often used differently in foreign language. Fonts are often used in print just to set of one language from the other and this is ignored in braille whenever possible. On this page, the language shift is clear from the formatting and the use of parentheses.
--Joanna