To keep your toddler boy from removing his diaper get some duct tape and wrap the duct tape around his diaper.
Just don't get the duct tape on his skin because it will leave gray color marks on his skin which will wash off but it will hurt his skin if you peel duct tape off his skin.
Just make sure you wrap the duct tape around the waistband of the diaper at least once.
The duct tape is hard to peel off and even I cannot get the duct tape off the diaper without scissors.
Duct tape is pretty strong and he will not be able to remove it with his little 2 year old hands and the small strength your 2 year old has.
You can also put your 2 year old in a pair of footed pajamas that zip up backwards or take a footed pair of pajamas and turn them around so that the zipper fits up his back and then put a safety pin such as a cloth diaper pin into it to keep the zipper from being undone.