That is beyond the scope of this guide. It is also not very common.

That is beyond the scope of this guide. It is also not very common.

Most likely, the 7-bit address plus the 1-bit read/write are being combined and treated as two separate 8-bit addresses. One for reading. One for writing. It's just a different way of thinking of the first byte (8 bits) sent after the start condition.

For other cases, it may be multiple targets buried in one chip. Each target has its own address in the normal fashion.

Yes. No. Maybe? Checkout this issue thread.

They're the "sameish". I2C came first, circa 1982. SMBus came along circa 1995 and added to it. SMBus stands for System Management Bus. They have some commonality at the protocol level, so there can be some intermixing.

See smbus.org for more info. Also, this article explains some key differences.