I can't help you on the first question except to suggest that you use the help buttons on the glossary set up page. I noticed that the help next to the "Display Format" gave some instruction as to how to create your own custom format, but it said it involves some understanding of PHP, so that's where I stop.
I think I can help you on your second question--as I understand it, the "Activity Names Auto-Linking" filter will set up linking so that when the name of an activity (resource, journal, assignment, etc.) is used in the course, there will be a link to the activity--just as terms in the glossary have links when used elsewhere in the course. However, there does seem to be an exception, though I haven't tested it extensively--
activities named in the glossary do not have the links to the activities outside of the glossary.
If this is the kind of linking you are looking for and you have admin access, then go into the Configuration panel, then to Filters and there you can make the auto-linking filter active.
Finally, I hadn't really used keywords in the past, but your question prompted me to look at the help button there as well (they are so helpful!) and I think that keywords could be useful when you have a definition that might be named by several different terms/concepts. For example, for the glossary entry "Martin Dougiamas," my keywords might be "Moodle creator," "Moodle Maven," and "Moodler Extraordinaire."