You could write an entire law review article on this tiny procedural dispute. In fact, several people already have (I suggest "Marie T. Reilly, Due Process in Public University Discipline Cases, 120 Penn. St. L. Rev. 1001 (2016)).
I don't have the time nor the inclination to write a new one for you, but hopefully a few scraps of law will serve to placate you and educate our wider audience.
First, public universities must provide each student with due process of law under the 14th amendment (Regents of Univ. of Mich. v. Ewing, 474 U.D. 215, 223 (1985)). (Note, private universities are not held to this same standard.)
As I asserted above, due process in an educational setting means two things: 1. notice of the alleged violation, and 2. a right to an informal hearing (Goss v. Lopez, 419 U.S. 565 (1975)). In deciding what constitutes due process and how much due process is sufficient, courts will generally balance a number of factors, including the interests of the state (the university) and the student. In Mathews v. Eldridge the Supreme Court held that the burden on the state for providing notice and a right to a hearing was "extremely low" (Mathews v. Eldridge, 424 U.S. 319 (1976). Conversely, the stakes for students are very high (See e.g. Dixon v. Ala. State Bd. of Educ., 294 F.2d 150, 158 (5th Cir. 1961) holding that "without sufficient education the plaintiffs would not be able to earn an adequate livelihood"). Violating a student's right to due process invalidates the school's attempt to punish a student and if the case is dismissed with prejudice the university will also be barred from pursuing further punishment. While violating one prong of a student's due process rights is enough to invalidate a punishment, making many small errors that would not by themselves constitute a violation can lead to an accumulation of errors that does violate due process (Furrey v. Temple University, 884 F.Supp. 2d 223 (E.D. Pa. 2012). These procedural requirements would have been the entire focus of an injunction hearing. The actual facts of the case (whether or not they did smoke) are not relevant until you get to the administrative hearing.
Again, we are talking about students who have been admitted to a public university and have been given permission to play on the team. There is no inherent right to attend the university or play on the team, but once the university makes an affirmative action to admit the student and grant them permission to play on the team, the university becomes bound by its own administrative rules and regulations. At that point the student also has a "liberty and property interest in an education" sufficient to warrant due process protections (Woodis v. Westark Cmty. Coll., 160 F.3d 435, 440 (8th Cir. 1998).
So, to answer your question, yes. The university did not have a legal right to suspend the team prior to fulfilling the students' due process rights.