First, some interesting reading (at least I think so):
From above comments: It's now been six months since the ceremony
I'm guessing here a little (call it a "slightly" educated guess if you will), but I very much doubt if the pet has yet been fully turned into dust, worm castings, soil, etc.
Buried below the surface of the ground, in uncontrolled conditions isn't the most effective way of returning the once living into "life" giving material. Also you're not going to get the "cooking" temperatures of something like, Composting Dead Swine:
Q. What about diseases, flies and pathogens?
A. Temperatures above 140°F (60°C) normally occur at some time in the composting pile. This is sufficient to destroy pathogens and prevent fly incubation. Good coverage of the composting pile with sawdust eliminates the fly breeding and incubation environment. No disease outbreaks have been associated with composting to date. Spreading finished compost in fields or pastures helps assure that disease organisms do not find their way back to the production area.
Also a good look around the web, "generally" recommends a buried depth of 2 to 3ft (600 to 900mm) for larger pets eg Cats, dogs, etc.
From above comments: From memory, not directly above, but close enough to spook. Carrots, baby tomatoes and a few chillis are planted there.
I honestly think you will be ok! especially with the crops you harvest from above ground, but please do remember I'm no expert on such things.
That said, I might be a little hesitant with the Carrots or any other deep rooted crop for the first year or two, seeing as the pet was buried "shallow". I would feel totally different about this, if the pet had been buried the "generally" recommended 2 to 3ft (600 to 900mm) below the surface.
Additionally if you practice "safe" harvesting techniques eg.
Wash, clean and store properly.
Discard any crops that look like they may be "damaged" somehow, or at least the part (area) that looks "damaged".
I believe you will further reduce any possible risk there might be that much more.
Hope the above helps a little, and sorry I couldn't give you a definitive answer.