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.
If you’re able to go to Serbia in December why are you delaying? You should move to Serbia now. If your wife was mistakenly called up to fight but then you stayed in Russia and it was clarified that she wasn’t drafted the situation has much less of an impact. If the argument was that she was drafted and she is unsafe you should be leaving Russia asap.