QB, yes but it is tricky. I think the QB needs to have a great relationship and connection with the other 10 players on the field.
Offensive line is the opposite IMO. I actually think having lower star rated players that play well together is better than getting 4-5 stars. I have been told on numerous occasions that offense line is one of the most inaccurate position to quantify in recruiting rankings and typically sees the most busts. Offensive line is all about how they communicate and work with each other and the offense as a whole. Coordination matters more than talent at times. This is why Arkansas' offense line (despite not being higher ranked) held up well or why Vandy held up against Alabama.