I just read the links, the first one, the ferret forum. That person was a crusade to end all people using oak based pellets because of the tannins. They were bringing up things of labs force feeding tanic acid though. As far as I know, my rabbit doesn't sit and eat the pellets in her litter box and she isn't being force fed tanic acid. I'm not trying to dispute the fact that oak is filled with tannins, because it is. But the majority of the information that that person was finding was what happens when you pump livestock full of tanic acid.
The second link from rabbit.org isn't about pine PELLETS its about pine shavings. Which we all know to cause issues. I've always been under the assumption that the phenols are baked off in the pelleting process and they weren't a risk. And the person who wrote that let her rabbit use a litter box with clay cat litter, which is a definite no no.
Sometimes I get a bag of pine pellets that has a stronger smell than other bags, but I let those things it outside in the sun for a day or two until they don't smell anymore. The majority of the time when I get a new bag of pine pellets, I let them sit in the trunk of the car for a few days or until I need them and that cooks whatever smell out there is.
I've never used the 'wood stove pellets' because they're not specified for animals; they're made to be set on fire.