Way overthinking this scenario. (note: they usually travel in groups of 2–3 thugs). Should they invade your home, knowing you are there (home invasion), you can assume they likely have already planned to shoot and kill you, beat you, rape you, etc.

Your ONLY concern at that moment is to eliminate the threat… Most home defense weapons (rifles that do not require a license) can have a clip size of up to 10 rounds. You should have at least (4) clips ready and loaded with ammo. A semi-automatic rifle, using high quality, high velocity, hollow-point bullets will take a human down within 3–5 rapid shots at close range inside your house. i.e. A single clip eliminates two threats and a quick reload of a fresh clip gives you 10 more shots if the third one has not yet run off.

You should never warn them that you will shoot, it eliminates the element of surprise, just start firing until ALL threats are eliminated (none of them are moving).

After that, call the police and let them do their job. You have no responsibility to render first-aid, leave that for the medical experts to attend to (you only open yourself up to a lawsuit if you try to help them survive their wounds and screw it up somehow).