Emulating 1-wire device(s) What I want to do is make a ATTiny IC become a slave on the 1-wire bus, with its own S/N and command list for its specific functions. 

What I want to know is if I can use the one wire library from the arduino site to send data as a slave. 

For example, you can have a slave in one room with multiple types of sensors which would report to the master on requested information, or the master can tell it to control something like blinds. 

Question
Would I have to monitor the bus line and respond to a request from the master and also take into consideration the way a normal sensor would send data? What frequency should I run the slave at to get the best functionality? 

I won't use parasitic power, as a note.
As far as I know, the 1-wire library you linked in your question allows only to act as a master, not a slave.

I've just released a library to turn an Arduino board into a 1-wire slave, here: https://github.com/neuoy/OneWireArduinoSlave (edit: moved here https://gitea.youb.fr/youen/OneWireArduinoSlave). I use it in my custom home automation system, and it works flawlessly in my setup (the 1-wire master, a DS9490R, is connected to a laptop via USB, and also provides power to the Arduino, which is an Arduino Uno). The library handles low level details: match rom, byte send and receive (which is actually quite hard to get right, mostly impossible without a logic analyzer). The rest is up to you.

It's entirely implemented with interrupts, all communications are performed in background, you can execute other code as usual, in parallel, and are notified by callbacks when bytes are received etc. Sending bytes to the master is also asynchronous.

I also know at least one other library exists, https://github.com/MarkusLange/OneWireSlave, as commented above by Ryu_hayabusa. It didn't work for me (don't know if it's because of my hardware setup or for another reason), but it definitely work for others, so also worth a try. It seems this library is not implemented with interrupts, so your program is blocked while waiting for master activity (which is perfectly acceptable in a lot of scenarios).