...i am less worried about the chemicals leaching than i am about oxidation.
I would be more worried about chemicals that oxygen. The fermentation process is only going to last a few weeks and then it is going in to bottles and/or kegs.
Oxygen molecules traveling through plastic is probably measured in molecules per year.
The alcohol in the beer acting as a solvent is more likely to leach out death. You will get more oxygen in the beer by transferring to a container than through the walls of the plastic.
Use only HDPE.
This is science as Tubercle understands it.