My name isXXXXX have over a decade of criminal
law experience and will be assisting you today.
I will take your questions as numbered:
1) Each substance is considered a separate charge; however, typically speaking the punishment will be the same and all run together. Sometimes you'll only plead to one charge and the others will be dismissed. It all ultimately depends on the prosecutor and the negotiation skills of your attorneys.
2) As I noted in my answer to #1, often everything will be look at as one incident regardless of the number of citations issued.
3) Sometimes this can happen. Prosecutors are very aware of this tactic by defendants. In a group situation, often the defendants will try to pin the illegal substances on whoever has the least to lose. Because of this, the person taking responsibility must be able to offer proof the illegal items belonged to them and no one else. For instance, all the items were by the one chair where he was sitting, or that the mushrooms were in a prescription bottle of the person who claims them. There must be something tangible that would allow the prosecutor to dismiss the charges against the others.
If you have more questions please feel free to ask. I'll be happy to answer them. If you do not, please do remember to rate my service in assistance to you today.