@LuminousAzael
Sorry for the late reply. I was binging all of the chapters so it's not in #5.2, but my speculation of "Ewey's real mother" is shown in #5.1, pg 10; where there's a worn lady with the demon spider pinning her down.
I speculate that may be Ewey's real mother because she has the same colour of hair as her. With also the reference that Ewey does look like her 'mother'
@vcnomnom : there are motivations for his proposal that do not require him to be a lolicon, this is to protect her from her family since as soon as her abilities are known she is more valuable to them then they know and will be desperate to get her back "in the fold".