…Show properties of your equipment (possibly very hard)…
$query = "SELECT s.name, i.item_quality, i.stack_count FROM item_instances AS i LEFT JOIN item_stats AS s ON i.item_stats_id_standard = s.id WHERE i.char_id_owner = $charid;";
Something like that should take care of that one, or did I misunderstand you?
That is certainly a start, yes.
Think damage per second against different types of armor, effects of items on stats and character properties (protection against different kinds of weapons), usage of items in crafting or as results of crafting, contents of books and maps, creatures summonable by that item, locks openable by that item. And that is just a short list from someone who doesn't know much about planeshift (me).
Please make sure that you understand me here correctly: If the things above should be disclosed or kept secret is a completely different discussion and won't be decided by me anyway.