Yes, this is documented in the _wind_vel_ hint on the component itself:

Data Collection or individual value for meteoroligical wind velocity
at 10 m above ground level in m/s. Note that this meteorological
velocity at 10 m is simply 1.5 times the speed felt at ground
level in the original Fiala model used to create the UTCI model.
Therefore, multiplying air speed values at the height of the
human subject by 1.5 will make them a suitable input for this
component. Default is a low speed of 0.5 m/s, which is the lowest
input speed that is recommended for the UTCI model.

I’m fairly certain the answer here is no, since the baseline UTCI calculation can’t make any assumptions about the source of the wind. Most ladybug components work this way, with transformations occuring upstream to reflect site-specific conditions.

Not sure, but you should check the type hints on the component, usually assumptions will be documented there (amongst other places).