need help identifing IC's and symbols from a diagram
The three components above are Integrated Circuits, or more vulgarly chips. If you want to search them on Internet for each one, add the 'datasheet' word to the one in question (Can't see the numbers clearly, but they seem 4532, 4508, 4572).
All the other question you asked seem to be, to some extent, specific to a certain software that has been used to make these diagrams. If you don't know, try to know what software was used to do the job, and then get to its help/manual/documentation.