Just keep waiting...keep the humidity and temps up like you said and then water the unsprouted ones when they need it...especially if you put the dry seeds straight in. But occasionally you will get a dud here and there, 1 that doesn't sprout or just doesn't get to the top, just stay patient and hopefully more will follow, 3 days actually isn't that bad yet.
*my most recent jiffy pod seed hasn't come up yet...its been a week so i think it's a dud but i just kept it moist in the hopes it's a late one.