So; your AP model cannot be converted to be fully managed directly in the Meraki Dashboard (those APs all start CW)
And your current Wireless LAN Controller (the EWC) cannot be monitored in the Meraki Dashboard.
For cloud dashboard operations, I think you'd need to use your existing APs with a supported 9800 WLC. Right now that would mean using a hardware Controller. One of these:
C9800-L-C
C9800-L-F
C9800-40
C9800-80
Note tht the latter two have, very recently, had End of Sale announced for them.
If you adopted this approach, the configuration of your wireless environment would (still) lie with the (new) WLC, but you'd get a high degree of visibility from the Meraki Dashboard.
https://documentation.meraki.com/Cloud_Monitoring_for_Catalyst/Getting_Started/Cloud_Monitoring_for_...