Since the SAT is new, and there won't be exact statistical admission averages, will schools use the same correlation guidelines published by the College Board to determine acceptance criteria? If not, how do they generate their own range of scores for freshman acceptance?
For the most part, yes, I would expect schools to use the correlation guidelines that are ultimately published by the College Board to determine an acceptable new SAT score range. The College Board has not yet published these official guidelines because they're still waiting on data from the May administration of the new SAT (they need stats from at least two different test dates to come up with accurate numbers).
Right now, colleges are in the midst of transitioning over their testing requirements to accommodate new SAT scores. Most people won't be applying to college with these scores until fall of 2016. Schools are currently making estimates of their acceptable new SAT score ranges based on logical predictions that assume scores from the old SAT can be converted directly to the new scale (we have a conversion calculator here that should be pretty accurate). However, they will likely refine these ranges over the summer after the College Board comes out with official conversion guidelines backed up by hard data.