Should the SIM card be in the iPhone or the Android phone before you start Move to iOS?

Hi and Help!! I'm moving to two iPhones from two Android devices.

1) should the SIM cards be in the iPhone or the Androids when I do the move -- which phone should be activated with the carrier?

2) has anyone used Move to iOS with an Amazon Fire phone (not full-on Android, so curious to read others' experiences) - that will be moved to the iPhone 6s

3) I'm moving HTC One to an iPhone 5s - again, any experiences that may make it easier would be appreciated.

4) I've read that Move to iOS only works with one phone per Apple account. I have to keep work and personal things separate -- hence why I have two phones. Does anyone have any advice on this working with two phones, or do I need to set up a separate Apple account for one of the phones?

Thank you in advance for any help -- I'm just a bit confused by the whole thing.

Kind regards.