I am considering purchasing a shotgun as well for home defense. I would not recommend slug or buck shots if you are looking for less than lethal. Also, if you have neighbors, you may end up shooting through the walls with those (depending on your range). The flash is (from what I read) not really efficient. It has a tactical purpose to it, and I don't think it would aid in a quick "grab the gun" scenario. Once you get the flash and boom off, you will both be sitting there def and blind saying, "Ok, now what?" The rubber bullets would be a 3rd choice for. They may cause serious injury, and they may put you into a serious legal issue if the guy survives. I would choose bird shots as my second choice. That is an effective, close range, shot that you don't have to be precise with your aim. It's point and shoot and stop the bad guy. It is a close tie to my first choice: which would be the bean bag rounds. I think you can safely deter home crime with a bean bag to the chest. Cops say they hit hard enough to knock a grown man down. It could be comparable to throwing a baseball really hard at someones chest. I would feel comfortable aiming for any body part with a bean bag round and know I will put second thoughts into the crook. It is also a good way to detain a criminal. If I chose beanbag rounds, I would have my real sidearm on me after I shoot. It is kinda of really strung punch to the face, but if you need to let him know you will do more than that, you can have your real gun drawn on the BG to make him get the message.
For me, I don't wanna think twice about shooting someone who breaks in. However, I also don't wanna kill anyone. I think a beanbag round for ME would be appropriate. Followed by a gun point to the BG with my sidearm. That way I can stop him/her AND still have a method to defend myself if it doesn't work (Which is why maybe bird shot would be more appropriate. You won't need the second gun, but you may have a mess to clean up).
I have only shot bird shot, slug, and buck shots though, so I can't give you any personal advice on the others.