Doubts about color spaces and chroma subsampling
Are YUV and YCbCr the same thing? → strictly, no. The former is applied to analog signals, and the latter to digital. But media apps (like Mediainfo) use YUV as the designated term.

It doesn't make any sense to say RGB 4:2:0, right? → Not theoretically incoherent, but I haven't seen any codec that implements subsampling for RGB pixels except for Bayer RGB streams possibly. Don't know its details. 

What is the "raw sample" here? → a stored single value of a pixel component i.e. any of R,G,B,Y,U,V (or alpha).

Is the 8 bits value referred to the number of bits used for each component (Y, Cb, Cr) before doing chroma subsampling? → it is the resolved bits per individual sample i.e. a 12-bit value has to be stored as a 16-bit datum, so 12 bits is the raw sample size and 16 bits is the coded sample size. 4 bits are for padding.

how should I calculate how many bits per pixel → in terms of luma/chroma resolution, it's the raw sample size. In terms of storage space for a raw uncompressed stream, you sum up the counts in the sampling scheme and divide by maximum count. Multiply by (no. of components x coded sample size).

So, for 4:2:2, that's

(4+2+2) / (4+4+4) = 2/3 and then 2/3 x (3 x 8 bits) = 16 bits per sample