I'll assume that this is for US admission to doctoral programs by those holding (or just about to earn) a BA/BS.
Any of those would be a plus in any application, though a preprint doesn't necessarily add much as it hasn't been reviewed. But none of them, alone, will be decisive in any application.
The reason is that most students that are admitted to most programs under the assumption above have none of those. The bachelors degree in the US is not a research degree but a generalist one. Even the "major" teaches only the fundamentals of a field in almost all cases. Thus, any research experience is a bit beyond the norm.
But, letters of recommendation are still very important. Applicants need professors willing to make a firm prediction of success of the person.
So, if you have an opportunity to do any of those, then do them. The ordering in your question might give a rough ranking of how they will be viewed by a committee if you have a choice. But most scholars would use a similar ranking in considering, for example, where to submit things.
There are also field effects. In some fields collaboration is relatively more important than in others. So, co-authorship might be valued. And in some fields, "first" authorship has no real meaning.
I also think it fairly unlikely that first authorship in a prestigious conference wouldn't already be matched with an outstanding GPA and marvelous letters of recommendation. So, the whole package would be screaming for acceptance.
Don't overthink it. If you can get some research experience and the rest of the "package" is good, you have a solid chance for acceptance at a good university. In particular, don't feel bad if all you have is a poster session at some conference.
For completeness, let me mention a few exceptions.
There are a few universities, UIUC comes to mind, that might emphasize research more in the undergraduate program (I have no specific knowledge of that, however). So graduates of such a program are more likely to have some research experience. But those students are also more likely to be accepted into doctoral programs because of the general quality of the program.
Second, there is the possibility of a truly exceptional student, someone who can, at an early age excel in some field. Someone "smarter than" most of their professors. They are unseasoned, but have a lot of potential. If that is recognized then they will be acceptable nearly everywhere, other things being equal.
Finally, some professor who sees an application of a person with some particular research publication, might be so intrigued that they prevail upon the admittance system to admit the student. Very rare, but possible.
But, even in these situations (except the last), the general picture with all its parts will probably point in the same direction.