Yes, Teletype comes with a keyboard if bought new.
Generally each I2C capable device has at least two headers / two rows of pins so you can daisy chain devices arbitrarily. There is some practical limit, as each extra device and set of wires introduces a little more capacitance, but generally you can do several devices without experiencing issues. It does depend some on how many I2C messages you are trying to send at once. Newer Teletypes (black PCB) are designed to host a few more devices than the older ones (green PCB).
I haven’t had a need for this, but some larger setups I believe have seen improvement from a powered busboard. Until you are trying to do a lot of I2C devices you shouldn’t need this.
No. All you need here is some kind of jumpers for standard 2.54mm pitch pin headers. Lots of options exist for DIYing these or buying them prebuilt, see here.
Actually connecting them once you’ve got cables is very simple: just connect GND <-> GND, SDA <-> SDA, and SCL <-> SCL between each module. I’d recommend reading this thread for more info about how the whole thing works.
Really don’t think so. I don’t recommend touching anything on the back of any module while it’s powered on, since the risk of shorting something to power is increased. I2C lines themselves pose a pretty low risk as the pins are weakly pulled up to digital power when inactive, and pulled to ground to signal. So if you get the pins swapped the worst that will happen is, for example, clock is always pulled to ground and nothing can use the bus. Often if you get the pins swapped, one or more modules will freeze up when you try to use I2C and will need a power cycle.
Can’t help you there, happy hunting.
