Friends Will Not Leave The Apartment, How Do I Get Them Evicted But Not Myself?

In November, we let two people we thought were friends stay here. They were *very* down on their luck. They are not on the official lease, but I do recognize that they are legally considered tenants. Since they moved in, we found out one of them is a drunk. A bad drunk. There have been arguments, issues with noise, I've been slapped, etc. They also have never payed rent or helped out with any bills, despite the fact they said they would by now. One of them is unemployed. For context, they are a couple. Who argue.
In our lease, it says we can't have a person stay for more than ten days at a time. We have had them "couch surf" every ten days anywhere from two days to a week. However, that does almost nothing for us. If we asked them to leave, they wouldn't. That's been made clear. If we attempted to evict them ourselves, they would be extremely vindictive about it and probably rat us out anyways.
Would it be enough to go to management and tell them they've been staying here, leaving for a bit every ten days, and just will not leave? I also just read as I'm typing and it turns out they aren't even supposed to be here more than 20 days in a 12 month period.
These people are making our lives a living HELL. Would it be horrible to just say we had them stay for only ten days, leave for a week, then they came back an it was supposed to be for just 10 days, but refused to leave? Hence why we are going to them? As that would make them tenants still.
They (the two people) wouldn't know it came from us. We would probably say one of our neighbors tipped management off. We are just very desperate. This *was* meant to be a temporary thing. We were trying to do something good, prevent two of our (at the time) friends from going homeless.
Please help. Any advice is appreciated. We are in the state of Oregon, if that matters.
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