Nobody would ever delete high quality posts. This is against the rules of community. If you keep to your campaigns rules, you get your stakes.
Yes. If you follow correctly the rules and regulations stated in the signature campaign then there's no way that your post will be deleted. But be sure that each post are informative and constructive for communities satisfaction. Then always observed dates cut-off time and the number of posts required in each weeks. For instance, if they required 10 posts per week then make it 12 or 13 posts to anticipate possible deletion and still you've within required.