I've spent the past twenty years advising against the use of PUA encodings for typographic variants on the basis that digital text is living text (unlike a printed page), that it persists and should … ((more))
I generally don't italicise those except # and % (which is a form of fraction, so follows the italicisation of the numerals. Some clients don't even want me to italicise parentheses.
But I am almost… ((more))
It depends what's included in the project, but typically it is bar, bullet, and any other meta-punctuation, then all math and logic operators, and arrows and other indicators.
Of course, bear in min… ((more))
Yes, because of their use as higher level and navigational elements, I don't italicise bullets. However, smaller punctuation such as period and midpoint (periodcentered) are normally italicised. ((more))