Glad to help you out.
1) How big is the online community, I am based in the US on EST, is there usually someone to challenge on a weeknight after 8:00pm?
Not that big, but big enough that you'll be able to get games going. If you go
here, you can see some statistics of players online along with games in progress and open. The total players online stat is a little misleading, but at most times, there are anywhere from 15-40 games up and running. I'd estimate that we have a core community of people who have been around for some time of around 75-100 people and we are adding new players on a regular basis due to marketing. Most of the time I'm playing is between 6pm-2am and there are quite a few people on then.
2) Are there still regular tournaments that are being held?
Depends on what you mean by your question. If you are talking about a tournament where brackets are used, etc, then no. We've never had anything regular and only had 2-3 official ones. There is however, a regular pantheon tournament. This really isn't much of a tournament, per se, and is a generally flawed system. Generally, pantheon works like this: everyone picks a side at the start of the tournament, light or dark (5 demigods on each side). Then, you can only play on light or dark for the duration of the tournament. Here's where the system gets a little flawed. There is no matchmaking based on skill. It simply queues up individuals based on the light or dark team they selected. So, quite often, there are big mismatches. Also, many games end up being 1v1. And some characters aren't exactly viable in 1v1 vs the stronger characters. Anyway, just about all of the very good games occur in custom games (imo).
3) What is the current state of the game, play, expansion, sequel ect?
We have modding, so we can fix things ourselves (as long as we can get other players to download and use the mods). AFAIK, there is no additional content planned for Demigod at this point. That might change when Gas Powered Games finishes Supreme Commander 2, but I doubt it. The game does have documented bugs. The stat system for the game can be exploited with relative ease. But, the game is quite a bit of fun, which is why many seasoned players are still here fighting it out.
4) I have been playing mostly closed single player games in the demo, i dont see an offline option in the demo. Is a single player mode offline available in the full game?
Single player is available offline. There is a skirmish mode and a tournament mode for SP. There's not really a SP story or anything all that exciting outside of some character movies for finishes the tournament mode with each player.
5) The BIG one, I noticed there was a 75% coupon code available. Does this apply to both the CE and Standard edition? Would any of the current members be so kind as to provide a noobie with the opportunity to purchase the game at discount?
I don't know. I gave my coupon code up. Check the various threads on the forum to see what you can find. As another option, I've seen there are target stores on clearance for $10 or so.
And last - if you do get the game, be sure to host NOOB games. Even if you feel like you might be great. If you don't want to host, make sure you join noob games while you are getting your bearings. If you want to use voicechat and play with the more seasoned folks, search for clan pacov on the forums and you can get the vent server info.