Just to get rid of the noise, disconnect the alarm horn that is mounted on the firewall. That will give you some peace when you reconnect the battery and fuses.

The alarm should have turned off: When you locked the car with the key. Try that a couple of times. It should have also turned off when you started the engine. Be careful with the engine start, it needs to run for a few minutes before shutdown so you don't get "lawn mower" syndrome.

You can tell when the security is off by watching the red LED on top of the dash.

As for a remote, the dealer may balk if the remote is not the original that came with the car. They typically charge one hour of labor to program a remote, and they like to supply the remote for an additional $150.

The remote does nothing more than the key. But it is nice when approaching the car from the passenger side and be able to open the passenger door.

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Keeping it running is better than buying new