Thank you for your question. I apologize for my delay in responding.
Please see the Addendum to The Nemeth Code for Mathematics and Science Notation 1972 Revision, 2007 Update Clarification Addendum, available here: [url=http://brailleauthority.org/updates07addendum/clarificationaddendum07.pdf]link[/url]
At the end of the document linked above, there is an example that I believe directly addresses your first concern. And I believe the example indicates that the vertical line you're asking about (which seems to indicate conditional probability ([url=http://www.rapidtables.com/math/symbols/Statistical_Symbols.htm]link[/url])) means "given" and should be treated as a sign of comparison. So, you should leave a space before and after the vertical bar, and letter signs are not need for A or B.