Hypothetically (swim isn't in any trouble........yet

)
SWIM has seen all the flexyourrights videos and has found them very useful; however, he has some questions that he believes are very important. (It's for swim's friend who needs advice).
Hypothetically, let's say there's a keg of beer and underage drinking occuring at a party, maybe some marijuana being smoked, but in the back and far away from the street (in other words, the smell wouldn't be noticeable). SWIM sets this scene since it gives the resident reason to refuse consent to a search.
Now, assuming a police officer walks up to the front door and then the swimmer walks out closing the door behind him (or even better...walks around the house and doesn't even open the door). This would take care of the plain-view rule.
The question is: If swiy is a resident of a house (not like renting...but actual resident), but is not the owner of the house....can the police detain swiy, and demand to speak with the owner of the house. Also, if swiy is a minor..and a resident...can the police demand to speak with an adult resident? What if they do not leave? In CA, the police are allowed to bring dogs to the front door and perform a sniff (which might smell the marijuana).
If they do demand the owners of the property, are there any courteous ways to hint that the owners are not available?
Sal-A