Correct. Everything seems to work, nothing happens weird on any software, be it the electrum wallet or coinomi. Only, no BCH shows up anywhere.
I think I'll just take the electron cash route soon. Moving coins to a safe wallet, then importing the electrum seed to electron cash. Seems to be the most reliable way, even though I wanted to stay away from Electron cash if possible.
As a follow up to all my previous posts, it seems as though Coinomi pushed an update on the Play Store (today? last week?), and everything works as it should now. I once again attempted to split my coins using the OP's method, and after the update, it has worked with no problems. The BCH are split successfully in to my Android Coinomi wallet, and the Bitcoin in my Electrum wallet is still there. Yes, I imported my keys without moving them first. Here to report that everything is fine now. It seems there was a bug causing things to not be imported properly, until today, I suppose. I tried again right after Coinomi updated, and everything worked as explained.