Making PageofPosts work with 2 categories

So I’ve been searching everywhere trying to figure out how to make this work and I feel like I’m close, but it still isn’t quite working. So I figured I would throw out a call for help and see if anyone has figured out how to make this work.

Basically I have page A with child page 1, 2, and 3.
Page A has custom field category -> W.
Child page 1 has category -> W, X. (Set up like that, so the explode can separate it).
Child page 2 has category -> W, Y.
Child page 3 has category -> W, Z.

So I want page A to display all posts tagged with the category A, then the child page to pick up on specific posts listed under two categories.

Here is the page of posts code (got it from another post I found on here). The issue is that have_posts() is returning false, even though I have posts tagged under the correct categories.

[Code moderated as per the Forum Rules. Please use the pastebin]

I’m using thedawn theme, so I’m not sure if that is affecting what WP_query is trying to do or what the issue is. I’ve printed out $category and $multicats and they are coming up with the correct strings. Printing out $args and $wp_query throw out a lot of info I’m not fully familiar with, but they are populated with some info.

If anyone has set something up like this before, I would appreciate any help.