I have say that I agree about iCrap and Android - the Essential I got just to upload cheques to Wells Fargo when they dropped support for the Windows phone with their app.It does say that, but, doesn't work. I tried it and it bricks the cellular modem and I had to reload a rom from PC to get it back. The modem files for dual sim are completely different than for single sim, there is probably a way to unpack the cab's in there and merge the single sim ones into the dual sim format but it's much easier to just get a single sim device. The dual sim stuff just really complicates things.
I've no idea on your Android question, never touched the stuff. To me using Android or iOS would be the same as using coke without a good high part.
At the moment voice calls go to VoiceMail and as Visual Voicemail is data driven it still works and I can call them back from another phone. The lack of spam calls has been quite refreshing.
I'll look into getting a single SIM XL.
Looking around for a single sim XL I keep stumbling over forums where the poster was kicking off that the dual SIM doesn't work with Visual Voicemail. Interesting, mine worked with that from the get-go. I seem to remember that if someone booted up a new phone without a SIM inserted that was an issue, and problems with 4G.