I recommend that anyone using a pull out motor replace as many sensors s you can afford, before putting the motor in. If your knock sensors are under the intake, just replace them now when it is easier. The intake and throttle body gaskets should also be replaced along with oil pan, front and rear main seals as well.
I can not tell you how many swap threads I have read over the years, hundreds easily. I can not tell you how many times I have read about sensor or gasket issues after the swap is done and running for a little while.
MAF position is indeed important. If you go to the GM performance site and pull up an LS# crate motor and then pull up the instructions you will find dimensions and orientation for it's placement for that motor. It may not be your motor but it is a good starting point.
This is a good MAF mounting solution
https://www.amazon.com/Airaid-9641-Hitachi-Adapter-Plate/dp/B00HJDJGN8