I would highly suggest talking to a criminal defense attorney about your case, as many facts are missing that are required to answer this question. The answer to this question might only partially depend on your relationship to the house. There might be an even more basic issue at play besides whether you had some sort of privacy status with the house. There might be an issue with whether or not police had reasonable articulable suspicion to seize you as an individual (if you were seized). There have been cases where parties have been busted by police where people were cited for underage consumption and the cited party argued they were detained without what is called reasonable articulable suspicion of criminal activity, leading to a dismissal of charges. State v. Becker is an example (see http://www.lawlibrary.state.mn.us/archive/ctapun/0304/1150.htm ) of a police party bust where there was an illegal seizure of a partygoer who was cited for underage consumption. I am not saying your case is for sure like this one but it might be worth talking to an attorney to see if a similar argument could be made in your case and if you have other defenses.
This post does not create an attorney-client relationship and is not intended as legal advice. You should consult an attorney about your specific situation for legal advice.
There are not statutes which interpret the 4th amendment. The first question is whether or not you had a protected privacy interest, then whether or not the police had reason to enter. No one could effectively or accurately answer your question based on the information provided here. You should consult privately with a lawyer, the charges will certainly not disappear if you do not have good counsel to represent you.
This response does not create an attorney client relationship and is offered for informational purposes only. Only a lawyer fully versed on the facts and circumstances of your case can properly advise you on the case. I am licensed to practice in Minnesota, not every state. You should always consult with an attorney licensed in your area on how best to proceed.
The answer to your question depends on thenrelationship you have to the house that was searched. That is an issue you need to discuss with a lawyer who can research it and prepare an argument for you.
This answer is not legal advice and does not create an attorney/client relationship. You need to speak to a lawyer to discuss your specific legal situation and to receive legal advice.