If your map is playable it's likely to be included as a skirmish map at least. If it's nice, it might make it into the campaign. We're a lot more open about maps than other things.
As for the hostage, you'll have to make it yourself. The game doesn't support "hostages", but you can have a model running around as a civilian, and you can choose where in the map you want civilians to spawn. We always need more civilian models so we could definitely use it if you make it.
I split this topic from the other thread.