Is there a reason they need to pee on the pads? Because honestly, I and several others on this forum have had not great experiences with them. They're very similar (from a dog's perspective) to other absorbent pad-like objects (rugs, bath mats, a dropped shirt, etc), and it also confuses the issue of whether it's okay to pee inside or not. I'd ditch them entirely and focus on training the puppies to potty where the big dogs do outside. Get an enzymatic cleaner specifically for pet messes (Nature's Miracle is widely available in the US) and thoroughly clean any spots where they've peed so they don't smell it anymore, then go back to basics with a strict potty schedule and rewards for going in the right place outside.
That being said, I don't envy you the work of two puppies. They're easily four or more times the work of one. Read up on littermate syndrome and make sure they're getting individual attention now so they can function apart from each other and bond properly with the people in the household.
That being said, I don't envy you the work of two puppies. They're easily four or more times the work of one. Read up on littermate syndrome and make sure they're getting individual attention now so they can function apart from each other and bond properly with the people in the household.