1) It's probably best if you can condense the prompts as much as possible. I'll be transferring them to a grid for the claiming post, so although there is no real limit, shorter is better.
Also, please keep in mind that many of the details you might want to include could be things people decide to tweak. Since it's not an exchange, someone might only use parts of your prompt. Like if you say, for example, "prefer no bottom!Snape", well, the person might decide to ignore that but still use the rest of the prompt.
2) Yes, feel free to submit the prompt again here. There are no guarantees. But there's no reason to let a good prompt go to waste.