Anyone trying to Develop Android 6.0 (marshmallow) ROM for Lenovo A6000/Plus?

Android 6.0 is out for Nexus Devices. Lenovo A6000/Plus is Entry Level Phone which may/maynot get Android 6.0 update. Remember the delay in the Lollipop update . I have contacted the Lenovo India via Twitter & they responded to have no information in regard with this. So I expect developers here to start deveoping a Marshmallow ROM for A6000/Plus could star

Is the Stock Nexus ROM for Android 6.0 enough to develop a ROM for A6000/Plus?
I am not a expert here & would like to see your responses....