Ok. I have confirmation that a member who had Gateway MR points with a Gold Credit Card (old card) opening a platinum charge got bonus points for the platinum charge, and the gold amex is now merged to Ascent Premium. Key point here - it was a new rewards program.
I think this key fact sheet
https://web.aexp-static.com/au/content/pdf/AU_KFS_Prop.pdf shows that the edge and explorer are in the same 'family' of amex cards - maybe you can only have one rewards account for all these cards - and it merges with the highest ranking reward program (e.g.. Ascent is better than gateway). No new rewards account = no bonus points.
Has anyone with an edge actually received the points? Either way, I know I won't be applying for edge until I'm done with this card for Mrs tizey