CQB shots at room distances are often taken via point shooting. Not out of doctrine, but instinct under pressure. That said, at 15 yards and under aiming with your weapon light works too. But if you want greater accuracy and speed under pressure, an RDS is the way to go. Tritium on irons is a waste of money as others have said. A novice trying to align irons in dim light in a defense situation is asking for trouble whereas a red dot is point and click simple.
As to the dot washing out when using the weapon light, there are a couple solutions. One is obviously having it bright enough, which I'd only advise in an RDS that advertises instant-on or 50,000 hour battery life. Two is closing the front cover on the RDS and using it as an OEG (occluded eye gunsight) but you have to range test that to check your point of aim point of impact shift for your unique eyes. If it's within acceptable range for home defense distances then you can run the sight at a lower setting and always be able to see the dot even if staring into the sun. Three is getting an etched reticle 1x sight like Vortex Spitfire 1x.
Lastly, if your family happens to be in a room behind the bad guy and you're forced to fire but worried about overpenetration, get on your knee and fire upward into his torso and rounds will likely continue upwards and over anyone behind. If you need to carry an extra mag on the rifle, something like the ETS mag with coupler is fine. Problem with home defense is there may not be enough time to strap on a belt or chest rig. In fact, I'd be worried about having enough time to put on a sling.