Yes, you can. Is it to start the bin?

Yes

They will eat anything organic. keep in mind worms eat the bacteria produced from the decaying organic mater then consume the mater as it decomposes. They are not particular as long as the material decomposes.

They will eat around what they do not approve of.

You probably can use that material for worm bedding, as long as you are very careful not to let it become waterlogged. Most worm bedding materials are better at holding air throughout the bin, like shredded paper, shredded cardboard, etc. Potting mix is designed to hold water to some extent, and may become too wet and heavy to be a good environment for composting worms.

Is there a reason why you want to use something store-bought for bedding, like potting mix, rather than something free that will probably perform better, like shredded paper or dry leaves?

I have decided on using shredded paper for the bedding. Simply because it's readily available. I agree theparsley that it becomes water logged.

thanks