How sure are you of Cantwell being rotated after the IB? Yeah, he was on the bench a lot last Championship season but he's been performing so well this season that it would surprise me a bit if Farke did the same now. If you still think he's gonna be benched a lot just get someone cheap like Dendoncker or something, you can't play 5 midfielders anyway and you'll probably want to have those other 4 outside in pretty much every match.
I'm skeptical of Otamendi, he's performed terribly lately so it's possible that Pep will rather replace him with Stones when he's fit again rather than moving Fernandinho back up to DM, and the chance of city clean sheets has seemingly been rather limited. It might be worth the extra funds to have someone like Kelly or Rico there instead and upgrade Connolly and play mostly 3-4-3, or maybe replace Ota with Doherty if you plan on playing 4-4-2.