"The Ukrainian Army itself held BUK exercises in the general area on July 16"
1. The problem here is that, Ukraine didn't have Buk systems near the place from which the missile was launched that hit 777. Trajectory would be different then and so your assumption is not relevant to the reality already. Ukraine forces would have shot the aircraft from behind, given possible set of positions they could chose, but 777 was hit from the nose.
2. Those territories, from which Buk was used, were under separatist control at that time and there was NO way for Ukrainian forces to quietly and quickly got that Buk deep into the separatists territory, made a shot, and then moved the system out.
3. Also, you forgot about images of that Buk with a missing missile on top that surfaced , and which (thanks to many photos with geotags and without) were traced back to the Russian border - simply put, Buks were quickly moved out to the Russian border RIGHT after !!!! hit the fan on the international stage. Another coincidence, I presume.
4. Local residents reported a loud noise and were seeing a missile flying upwards and to the north-west - that was at the location which separatists were controlling and it which the Buk needed to be in order to hit 777 the way it .
5. There were even photographs of a smoky trail that was left by the missile. Location where those images were shot, matched the location on the updated google map where dark burns in the field are + marks on the ground where heavy equipment was maneuvering and taking positions and it matches the location of the village where locals reported the missile. All that matches the location from which Buk missile needed to be shot in order to match the damage done to the aircraft.
Sorry, but even if every single one of this facts are not that much to get a conclusion, but when they are held together - that pretty much leaves very little chance it to be a non Russian missile.
