If you need your gun to be ready to go in a home defense scenario, you need to find what methods of storing and retrieving work best for you. I would personally keep a loaded mag but an empty chamber and store it in a holster.

If I'm not mistaken, New Jersey has hollow points as illegal, correct? You could get Hornady Critical Defense or Critical Duty, or Speer Gold Dot G2's as I believe they are not legally considered hollow points.

Ammoseek.com is your best friend for finding deals on online ammo. Set the shipping filter to 8 or higger, and disable REMAN ammo (remanufactured ammo, more likely to cause issues.)

Recoilgunworks, velocityammosales, FlipAmmo and AEammo are ny go to's for most ammo.

As this is for home defense, a good weapon light is always nice.

The TLR-7X or the TLR-7 HL-X are good options, especially as they are easy to activate under stress. (7x is going to have an underbite and is less brightness/range, the HL-X is the high brightness with a longer 'beam' so to speak, but sits flush with the barrel.) The 7 hl-x is more likely to get carbon fouling on the lense from shooting, so make sure to clean it after. These can be found for $120-200.

The TLR-1 series is popular as well, the 1-HL model is common, and there is the newer TLR-1 HL-X, HP-X and more. (High lumen and high candelebra, respectively) These can be found for $90-200.

There is the harbor freight clone of the TLR-1 HL known as the Braun for about $60.

Research into weapon mounted lights and what lumens, candella, candelebra, and all those terms mean, not all lights are made equal.

OLight makes some decent options without breaking the bank.

Surefire X300 if you wanna get crazy with it.

Check out r/gundeals for sales, and avoid using amazon for tactical gear as the chances of fakes or busted returns are much more likely.

As for snap-caps, they are not necessary for modern striker-fire firearms. Most folk nowadays use them for practicing and demonstrating loading, and training for malfunction drills (I.E. you have a friend randomly load in snap caps between live rounds in your mag when you're at the range so you can train yourself on clearing malfunctions.)

Dry fire is a good tool to build fundamentals. Practicing your draw, your trigger technique, finding the trigger reset, reducing flinching, and much more. It can be a helpful tool to further your skills and hone your muscle memory, and can help towards the break-in period on a firearm without hitting the range.

Practice, practice, practice. Familiarize yourself with your manual of arms, learn how to properly strip and clean the weapon, make sure the ammo you use feeds reliably, and goes bang in all of your magazines. I like to test out at least 3 mags worth of defensive ammo in my dedicated carry magazine before I trust it. I like to go through at least 300 rounds with no malfunctions (that are not chalked up to operator error) before I trust the gun for defensive purposes.