"At this point, it's pretty much a done deal. We're just formalizing it," said senior Christopher Boyle, the group's president emeritus.
"It's really just the fine details — things like how the room will be set up — that's holding it back," he said.
Boyle said the organization, which he restarted last year and now has 40 members, first reached out to Yiannopoulos' manager in June.
The Halloween appearance is being opposed by another group of students, who say Yiannopoulos is a purveyor of hate speech. They have started a change.org petition in opposition to the event. It has gained nearly 3,800 supporters.
"We call on admin to block any attempts to bring these hateful leaders to campus. … Hate speech to incite violence and threaten the lives of students is not the same as free speech of diverse opinions," the petition from the Students for Quality Education reads.
Yiannopoulos is currently arranging a number of cross-country speaking engagements that he calls his "Troll Academy tour." He would not say for certain whether Fullerton was on the list.
In a text to a Los Angeles Times reporter, he said "Naturally, I'll be visiting a lot of colleges in California. It's the craziest state of all. We will be announcing our tour dates soon."
The 32-year-old previously worked as the Tech Editor of Breitbart News and has sought out controversy at every turn of his career. An early supporter of
Then in February, he resigned from Breitbart after video was released showing him making comments that were interpreted as being supportive of pedophilia.
Around the same time, the town of Berkeley descended into violence as protesters took to the street to stop a planned Yiannopoulos event on campus.
That speech was canceled, but he will be returning to the liberal enclave late in September. Already, his upcoming speech is drawing ire from local leaders who fear a repeat of what occurred in February and last weekend.
Berkeley police estimated that more than 4,000 people attended what were mostly peaceful displays of opposition to Trump's agenda on Sunday. Still, by day's end, 13 people had been arrested, one on suspicion of assault with a deadly weapon and three on battery charges.
A spokesman for Cal State Fullerton said that Yiannopoulos' speaking on campus hadn't been confirmed, but if it is, "we will engage in appropriate planning in these weeks before the event."
"The value of free speech notwithstanding, the law is clear. Hate-speech codes that have been enacted by some colleges and universities have been declared unconstitutional when challenged in court. While many on campus and in the broader community may find Mr. Yiannopoulos' remarks distasteful, if not wholly objectionable, even hateful speech is protected speech," said Fullerton spokesman Jeffrey Cook.
Cook said the appearance would be a closed, ticketed event.
"Mr. Yiannopoulos is a controversial figure, but the University administration does not play a role in determining which speakers student groups may invite to campus," he said.
Boyle, of the campus Republicans, suggested that the group's decision to invite Yiannopoulos was not a blanket endorsement of his views.
Boyle said he and others were taken aback by Yiannopoulos' comments about men having sex with teenage boys.
"Those comments did give us pause. I found them very offensive as a Catholic who has had to grapple with the failings of the church," Boyle said.
"People who are self admitted provocateurs are going to cross the line occasionally. It's good that he apologized and attempted to do penance."