I'm a bit confused, so I need some clarification.
1:each email account has different Alexa accounts and you wish them to be linked?
2: Alexa still sees your old configured devices and you wish to remove the old ones but can't?
3: you can't log into the Alexa App to see what is being seen as online? The off line devices would be your old devices and you just delete them.
https://alexa.amazon.com/spa/index.html#cards4: Alexa sees most configured modules in HG even dummy ones. If your not using the virtual modules delete them from HG the from Alexa.
5: Alexa sends device commands to devices depending on how they are setup in HG x10 RF or PLC or zwave or wemo(http) So if your wishing to send RF to a device it needs to be setup in HG as a RF device.
I've yet to do this my self but I know it is possible as I use a cm19 for my Alexa control.
I had Gene add this for the Cm15, believe you need to send raw RF maybe using a wizard script.