You're right, you shouldn't expect much from 4 month old puppies. If they're going in the house in places they shouldn't it's because YOU let them go there! There really isn't much room in a kennel, regarless of how huge it might be, with two puppies and a wee wee pad. Why not try an excercise crate? that way if you have a wire crate you could hook the ex pen to the sides or if you have a solid kennel you can put it inside the ex pen. Either way you can put the wee wee pads (and I would suggest using more than one!) outside the kennel/crate. You're not going to confuse them. At 4 months they are physically NOT CAPABLE of 'holding it.' At that age their bladder is working pretty much on reflex: bladder fills and stretches, stretch receptors in the bladder wall sense the stretch, nerve impulses are sent to the spinal cord and a reflex is activated, relaxing the sphincter muscle that holds the bladder closed. At their age they're not able to do much about that. Just as you can't expect a baby to be toilet trained at three months, you can't expect dogs to 'hold it' at four months.
Viralmd, Cyril (aka Aljac Captain Hook CGC) and Tassie, the rescue chihuahua