Hi RobinPandey ji,
Thanks for your wishes and I wish you too good luck and hope for a speedy processing of your file.
Regarding your questions, I think you did the right thing by not sending your passport now. You can send it at the final stage after Decision is made. I read about couple of people doing same. This should not be a problem at all. The only thing that can happen is little bit of delay in the over all processing time, I guess it may take max of a month more time. But since you are in US, it is not recomended to send your passport now and get it blocked with NDVO for long time. The good thing in your case is, you can try to go for visit visa to Canada, so that you can travel here to visit your wife.. or else, even she can visit you any time in US...
Regarding eCas status, it is not reliable. So do not worry about eCas status... my eCas always said as application received until 5 days prior to recieving passport. It directly changed to DM from Application Received.
Regarding your medicals being sent electronically, I think it should be fine, since it has been confirmed by embassy too (as per your lawyer).
Good thing is you didn't get any documents request so far... I hope as per documents they are good and satisfied. May be in next month you may think of applying for GCMS notes just to get a bit more information about your file processing. About GCMS, you can check my earlier comments (posted on 6th Sep) above.
And regarding my visa office, first I submitted all the documents to Mississauge Office (which is same for all of us, even your forms might have got submitted to Mississauge by your wife) and after sponsorship approval file got transfered to my wife's residence country which is India. Even for you it will be same. But if you are staying for longer time in US, then not sure if you can get the file transferd to US instead of India. Because, you can not post your passport to India while you are in US. May be you can try emailing Canada Immigrati