What are the restrictions on editing and deleting messages in the chat rooms? The first time I tried it the options were there, but they went way.
You can only edit or delete your message within 2 minutes.
According to the Chat FAQ,
How do I talk?
If you make a mistake when entering a message, press the ↑ up arrow to edit your last message … or press esc to cancel editing. You have 120 seconds to edit your messages. All edited messages have a small edit indicator.
That restriction also applies when deleting messages, and also for regular users and even Room Owners. Only moderators and SE staffs can bypass this restriction; editing/deleting anyone's messages at any time.