Seems like you have a pretty good understanding of them already. “Blade” needle is more of a European term for piercing-specific needles, but the needle itself is essentially the same as a cannula needle minus the hub and sheath. Here is a typical US “blade” piercing needle.
A cannula is a flexible plastic sheath covering a medical needle. For medical use the needle makes an entry point and is slid out while the cannula is left in a patients arm and used as a flexible hub for IVs. For piercing use the needle is pulled out leaving the cannula, jewelry is inserted into the cannula and slid through the piercing. They’re used very commonly with externally threaded jewelry in places like Europe where they have looser restrictions on medical devices. Here are two images of cannula needles, first the complete medical device.
And here is a close up to show the plastic sheath “cannula” over the needle.
O-needles and chamfer needles do work in a similar way as biopsy punches but the important distinction is they are manufactured specifically as piercing needles so you are not limited by medical device restrictions. Here is an Industrial Strength “chamfer” needle.
You might notice the blade section is very similar to that of a biopsy punch, but on a smaller scale. To be clear, biopsy punches are intended for medical use and are not accepted by the APP for use in body piercing.
Hope this helps explain them a little, good question.