The only issue is: in order to have a cliffhanger for Ian, you must play with him before the end of the chapter. Looking at the way the development was done until now, we can assume that in chapter 10 you will play with Ian first and after that with Lena. Sure, Eva could mix Ian and Lena story or she could simply add one more scene at the end, but I hope she won't go on that route. Changing the story or adding even more stuff than it was initially planned will only drag the development for a longer period of time.
I think it is too soon for Allison to get pregnant. We know that she took the plan B after the last date. Even if you sleep with her again in this chapter, there should be at least 2-3 weeks between that point and the one where she thinks about a pregnancy test. Also, we don't know if there will still be a time skip in the story. If it is, I doubt that Eva will want Ian to have a kid with Allison after the time skip. The story will end there for Ian.
Gillian could be this chapter plot twist, but even if she is Mike gf, why would she go back to Ian that fast? I also don't think there is any reason for Ivy to blackmail Ian. There is nothing that she can gain from that.