Hi sognaz,
I know for me it took a day or less for the posts to get approved. Don't worry, they will get to your posts and you can enter chat in no time
As for chat, there are no specified hours. You can enter whenever you wish. There is however a calendar for the scheduled topic chats. These topics are hosted on a weekly basis. Note that all times are in Eastern Standard Time. You can find that calendar here:
Forums at Psych Central - Calendar
I'm not 100% certain about all members living with MI. But I do believe a good portion of us are (or know someone else who is) afflicted with a mental health concern.