You are correct, the criminal code is silent on what use of force is authorized however the Supreme Court of Canada has ruled that lethal force is not permissible to protect property. Look into the R v Gunning [2005]. If it turns into a self-defence situation, which I believe likely to happen when confronting criminals, then you may do what needs doing.
I completely agree the criminals are at fault and the presumption of innocence is paramount. However, when a life is taken expect things to get messy particularly when special interest groups are involved.
Glad it's worked out for these gentlemen and none are locked up.
Interesting about the Gunning case.
With regards to the current discussion, the most important part of R V Gunning is found at paragraph 26.
https://scc-csc.lexum.com/scc-csc/scc-csc/en/item/2228/index.do
It is common ground between the parties that the intentional killing of a trespasser could only be justified where the person in possession of the property is able to make out a case of self-defence: see R. v. Baxter (1975), 27 C.C.C. (2d) 96 (Ont. C.A.), at pp. 114‑15; R. v. Clark (1983), 5 C.C.C. (3d) 264 (Alta. C.A.), at pp. 272‑73; R. v. Bacon, [1999] Q.J. No. 19 (QL) (C.A.), at para. 24. Mr. Gunning does not raise self-defence in respect of the shooting; he raises the defence of accident. Rather, the defence of property is raised in justification of his use of the shotgun prior to its discharge.
All parties actually agreed that you can use lethal force in defense of property ONLY if you can prove self defense. Now that may seem counter intuitive, and anyone who has read the current version of the criminal code is tempted to think that defense of self and defense of property are two clearly distinct situations. They are..now.
In 2000 when the original event happened, they weren't. Here is the archived version of the criminal code from 2003.
http://laws-lois.justice.gc.ca/eng/acts/C-46/20030101/P1TT3xt3.html The Justice Laws website does not have online archives back to 2000, but it the relevant sections were not amended in the meantime.
At the time, it was clear that lethal force was only to be used as a last resort, regardless of whether talking the person or the property. In order to prove self defense you had to actually prove that you tried and failed at lesser means, or that the situation was so dire that you couldn't try.
Specifically with regards to property, if you tried to prevent theft, recovery property, or evict tresspassers, you weren't allowed to use lethal force at all, unless the criminal actively resisted or used force to
continue the theft
after you tried to evict them
without lethal force, after which time it would be deemed to now be a self defense issue, whether or not there was an actual threat to the person. If a criminal passively without force evaded your attempts to evict them peacefully, this would be deemed an assault, at which point, having been 'assaulted', you could use greater force and eventually lethal force to remove them from the property, in the name of self defense. It really was poorly worded, and self defense cases were always a mess, and it wasn't uncommon to see lots of issues with judicial instructions etc as you see in Gunning.
Regrettably, Gunning did not argue self defense (because of a brutally incompetent judge who told him in advance it wouldn't work, despite the fact that it was a jury trial). Had he of argued self defense, which he clearly could have, it would have been a very different case. In either case the Supreme Court actually side with the accused, and tossed his convictions.
You should also know that because our self defense laws were completely re-written in 2013, the case is essentially of very little value in informing today's self defense and defense of property cases.