I think Kyle to the one is just temporary. I think if/when all are healthy (July) there is not a place for Kyle. IMO, Alzolay will be out for the year. With that in mind this is the 13 I would have on the staff: Steele, Imanaga, Taillion, Assad, Wicks, Leiter, Neris, Merryweather, Wesneski, Brown, Smyly, Miller, & Almonte. The only 2 with options left are Brown and Wesneski. They lack a closer. That would be what I would look for at the deadline. That would push everyone back a spot in their role. Kind of what the Dbacks did when they got Seward last year.
If/when they change anyone out either Brown or Wesneski would have to be sent down. None of the others could be without clearing waivers. For now, they Cubs can mess around with that 4th and 5th spot. Mainly go Assad and Wicks, but if you want to limit a few innings you can skip them and plug in Brown or Wesneski once or twice. You can also start one of Brown or Wesneski to give the entire rotation an extra day.