HRM Question(s)

Options
I am actively shopping for a chestband heart rate monitor. I will be using it with my Samsung Galaxy S5.

I'm confused about the different ways that HRMs communicate with the device. I have read some use Bluetooth, but it seems like there are other connection options too (depending on what the device and the HRM support).

Two questions....if I get a Bluetooth HRM, will I be able to use Bluetooth headphones on the same device? I currently use a Bluetooth headset, and I don't want to have to go back to wired earbuds.

Second, is there a good website that someone can recommend that will give me the HRM 101 information to help me understand the basics of how to shop?

Thanks in advance!