My labels come from U-Line and they truly are waterproof and will even stay on the container when soaked in water (I tested). I have a Samsung Printer and when I print the clear labels I use the setting for photograph as paper and then just use the normal toner setting. For the white ones - I use the label setting for paper and normal for toner.
The reason a laser printer works is that unlike an inkjet that just lays the ink on top relying on the substrate to absorb it, lasers use toner which is sealed into/onto the material using heat. It is really important that you only use products meant for laser and that you adjust your settings for each type of printing you are going (label, photo, cardstock, etc.) If the labels are not meant for laser printer then the heat is going to remove them from the backing and create a mess.
HTH