You can go to the, let’s say, #bug category and select New. All the new topics will then appear in order for you.
Yep. You can use the solved plugin, which allows users and staff members to mark a post as the answer. I would also recommend enabling Tags. Tags will help you not only keep everything more organized, but will also let you know which question has yet to be answered.
Below you will find useful tutorials for every feature I mentioned.