In my opinion, Chapter 135 will begin with Shinobu going to Fumi's apartment. We already saw in the previous chapter that it's normal for Shinobu to stay over at Fumi's place. He may not have officially moved in yet, but after seeing them shopping together, it's pretty clear that they've essentially been living together while working on the screenplay. Since the script still needs revisions, there's a good chance Shinobu will continue staying at Fumi's place.
I also think it's still too early for Shinobu to meet with the producer. The producer only recently asked him to think about the proposal, so he would probably give Shinobu at least a day to consider it. Besides, it's already late at night in the story, well outside normal working hours. (In Japan, people generally take business hours quite seriously. Unless it's an urgent matter, discussing work after hours—especially with someone in a senior position—is uncommon and difficult to arrange.)
As for Shinobu and Fumi's conversation, I think Shinobu will finally confess his feelings clearly, telling her that he loves her for who she is and not because she reminds him of Sakura. I also expect there to be a few pages showing them sharing an intimate moment. Personally, I think if this conversation were instead used to reject or break Fumi's heart, it would negatively affect Shinobu's film. With so few chapters remaining, that would only make the story even harder to wrap up properly.
On Sakura's side, I think Mio will drive her to Mio's grandmother's house to let her rest, where everyone involved will explain Shinobu's situation to her firsthand. They'll tell her how he spent months struggling with depression and isolating himself until his new project finally gave him a reason to move forward, which is why he had been staying somewhere else. As Sakura learns all of this, she'll gradually realize that she has misunderstood Shinobu all along.
The following day, Shinobu will present an alternative to the sex scene to the producer. Personally, I think he'll draw on his previous experience gravure to come up with a substitute that conveys the same emotional impact without requiring an explicit sex scene. This idea may even have come to him after Fumi unintentionally mentioned Sakura, prompting him to reflect while walking alone. The producer will find the concept interesting and ultimately accept the proposal.
Meanwhile, after learning the truth, Sakura will confront the fuckboy and break up with him. During their argument, he might accidentally reveal the same things he previously told Shinobu at the café. After that confrontation, Sakura will likely decide that she needs to meet Shinobu, setting up the events of the following chapter.