Dear Sir,
1)
There are 14 bits of data which are left aligned on 16 bits word.
The data is placed on bits 13 down to 2, bits 1 and 0 being nothing. I Q interleaved means that the sequence in the buffer looks like the following
I0Q0I1Q1I2Q2I3Q3...
2)
I will get one of my colleague to provide you with this information, it is not part of the user manual indeed.