How best to split up a comprehensive literature review
I would try to do 4* topic papers (one on on each subtopic within section 3).  Then do a wrapup.  I.e. 5 LPUs.  

In the four topic papers you can be a skimpier on the methods (or perhaps go full bore on methods in first one and skimpy on others, but "referring" to the discussion in first one.)  The wrapup will "review" the previous 4 and make some general observations (cross-correlations, etc.).  I would be brief on definitions (less than currently in there) for the 4 topic papers.  Just basics with some footnotes (skip history entirely).  You can go more in depth on history in the wrapup self review paper. 

*If a couple naturally combine, fine, do 2 or 3.  But 4 is fine too:

P.s.  I'm not an expert in your topic and I really just glanced at it.  But what I saw looked solid.

P.s.s.  Chopping into LPUs is not sleazy.  It's actually in some ways more efficient to process (at least for a reviewer!)