Came across these in the Haliburton area (Ontario, Canada)
Anyone have an idea what these white things are? I assume a fungus of some sort, though they look almost floral. And at one point I saw a bee/wasp poking around inside these like they would do with flowers so further confusing me as to whether fungus or flower??
And would I be correct in assuming the yellow one is poisonous?
I can't tell you about the yellow one, but Mike probably can.
The first one is not a mushroom, but a plant that has no chlorophyll, hence the white color. It is commonly known as Indian Pipe and more officially as Monotropa uniflora. Wikipedia has a reasonable and short discussion of it.