Question about Linx RF module's (HP3) datasheet

[Megahertz]

I have read datasheet of the above modules (TX & RX) but I would like some help understanding two key points in the datasheet (attached).

Firstly, if I want to select the channel serially, I take the clock pin HIGH, data pin LOW, both I believe can be connected directly to any free pins on my PIC (set as outputs), and then use debug statement to transmit binary value of between 1 to 100 to the data pin (for example "DEBUG 01100100 " for 100 & " DEBUG 0011" for 3, and immidiately after doing this take and keep clock and data high all the time.
Secondly, should I send 8 bits every time? like for 3, should I always send "DEBUG 00000011"?
Thirdly, will sending data this way will make LSB go first?
Fourthly , is this a correct process to set the channel I want to use serially?

And LASTLY, at page 10 of the datasheets, under the table where serial channel chart is on the right, I am not sure what colum 3 means under the heading "RX LO" & also why on both Tx & Rx datasheets it is only mentioned TX Frequency & not RX centre frequency in the RX datasheet?