I don't remember what else is done at the 16 week appointment, but I know she will:
* check your blood pressure
* check your urine
* ask how everything is going
* ask about your scan (she's probably already seen the written evaluation, so if she asks it's just to get an idea of how you felt about it)
* update you on your blood results from your booking in appointment, and perhaps confirm your chances of the baby having downs, based on the bloods and nuchal translucency you will have had checked at the scan.
As for the heartbeat, she should check it. She will use a doppler, and you will both be able to hear it as well as her. It's a small piece of equipment, see here: https://www.aurorabioscience.com.au/images/summit_doppler_no_display.JPG so even if she does a home visit, she would most probably have it with her. The holes on the front of the handheld box portion of the device is where the speaker is, and it will emit the sound of the heartbeat to the entire room. She may not tell you the baby's heartrate though, so you should ask if you want to know.
Good luck honey; hearing the HB is a wonderful experience.