I appreciate all the thoughtful replies in this thread, especially from Armoured. A quick update regarding myself and perhaps other facing a similar situation: me and my wife will stay in Serbia from December until early Spring at the minimum. Background & Eligibility for wife has still not been started (Medical done in March). We will soon be applying for a TRV for my wife before she leaves Russia - our child will soon receive his Russian passport and a Citizenship Application will be filed for him in the Canadian Embassy in Moscow. In Serbia, we will do an LTV (temporary Canadian passport) for him.
If anyone can believe it, a police man came at night to my wife's apartment and handed her a military summons (she worked as a school teacher?!). Thank God almighty her mother was there to help and went to the military office in the morning to confirm that it was all a mistake. We will be using this as part of our evidence in the TRV application. We will stress in the Visa application that for compassionate/humanitarian reasons, that it be approved so that our family will be reunited without this constant looming threat. Hopefully they are not so heartless.