Sounds like this is an intrapeneurial venture and we are your google higher-ups. As a teacher, I love google classroom. I use it for just about everything and there are a number of things I wish they would add. My understanding though, is that google has stated they do not want google classroom to be a full blown LMS. Your presentation will have to convince them (us) otherwise.
I like your added features. A parent portal would also be very welcome. As a corporation, I would like to here more about how these features will gain us customers. Are we losing customers for not having these features or are we alienating teachers by not having them. Survey data to support your chances will help your proposal to carry extra clout.