So, over the next couple of years LM will require 2 extra EMUs for Bromsgrove, 4 for Chase valley and 1 or 2 for Coventry/Nuneaton, hence 7 or 8 units. I note that Northern require 9x 323s to cover Manchester-Alderley Edge-Crewe including the Airport stoppers, whilst 7x are required to cover the Stoke and Hadfield turns.
Note that Northern are required to introduce an additional hourly Manchester-Macclesfield service by December 2017 which will probably be 2 extra diagrams.
DfT have said to bidders of the next Northern franchise to assume they can take on all the trains Northern Rail currently have minus one class 153 which will be transferred to EMT, as well as the option of subleasing some 185s from TPE for the some of the lines taken over from TPE.
It's possible some bidders have already started their bids on the basis of keeping all 17 x 323s. Maybe one or two will have proposed releasing the 9 x 323s you mention being used on Alderley Edge/Crewe/Airport services on to Preston services allowing some 6 car workings?
Although that doesn't rule out Northern subleasing trains to another operator if they are returned by April 2015, like when FNW subleased 2 x 158s between when the TPE franchise started and the new Northern Rail franchise started.
I thought about whether Porterbrook want to give their 323s overhauls while there are EMUs sat around spare. It seems the LM 323s are due their C4 exams this year and next but no 323s are due C6 exams in the near future:
http://www.porterbrook.co.uk/downloads/6YearPlan.pdf