MCP3201 ADC timing clarifications
The data is clocked out, MSB first, simultaneously with the ADC converting the input. A Successive Approximation Converter (SAR) evaluates the MSB, then the next, and so on down the the LSB. Each bit is spat out as soon as it's ready, so the conversion is complete by the time the whole word has been clocked out. 

That's the fastest way to use the part. If you want LSB first data, you have to wait while it converts it MSB first, then keep clocking and it will spit out the data the other way round. That however slows the part down to about half the MSB-first speed.