The comment I wanted to make is a second note on the variances between our three puzzles, specifically concerning the number of unmarked polyominoes. As you have already mentioned, your puzzle uses eight different givens. This also means that all eight polyominoes are labeled. In his puzzle, Cameron labeled seven polyominoes, leaving the monomino unlabeled. My puzzle continues this pattern, leaving both the monomino and the domino unlabeled. In addition, two of the givens in my puzzle (specifically the '4' and the '5') can switch positions without invalidating the puzzle.
I considered doing this when I noticed the 'parity apartheid', as you put it. But, I decided that the current setup was more interesting.

As for solving my puzzle, a hint I would give to people who have not read the contest rules is:
Add together the values of the eight givens and compare that total to the number of available squares in the puzzle.