Ok.... going out on a "limb" here. Do we have ANY PROOF that any type of driftwood is a problem? Honestly, think about it. Are their streams that don't have fish because a pine tree or cedar fell in it? I have NEVER given it a second thought about what wood I can put in a fish tank until the internet. Are we overthinking this? I know for a fact that I've had Pine, cottonwood, and ash in my tanks and have never had a problem. I live in an area with pretty much zero hardwoods and I use wood I find. Sure softwood will not last as long as hardwoods but is that a problem? Other than softwood taking a ridiculous time to become waterlogged and sink, I've never had a problem with it killing a tank. This very second I have a 40 long with a dozen clown plecos that are doing GREAT and it has about 15lbs of some soft kind wood. No problems at all. Personally, I think that pretty much any "DRIFTWOOD" (IE from a stream that has lost all its bark, rounded corners etc.) is fine.
Edit: One thing I do is boil it and if it smells like pine or anything questionable I just dont use it. It usually smells like....umm dirt?