Never used a torque wrench on brake bolts. Just don’t go silly with the torx key. It should be a size fitted to most decent multitools – I guess it is a bit naughty of them to not send the correct torx key and technically the blue threadlock on them (if there is any) is now useless but no more so than if you took it off to clean it and tbh a barrier to stop them corroding is more important as that makes a mess of your hub.
Just nip them up using one finger on the torx key and that should be about 5nm if that is what they need. you can get torque keys for about £12 from superstar if you must.
What do you do when you adjust brake and shifter angles on your bars? Assuming you do adjust them instead of just riding how they came from the shop?