Bedtime Manipulations

I am sure every parent has had trouble at bedtime with children manipulating the system and trying to squeeze out a few more waking moments from the day.  If you haven't battled this time of the day or aren't anymore, please let me know what you're doing.  We have a very set routine for the twins.   Bath, PJs, Teeth, Books, tucking in.  Even the tucking in process has to be sequenced perfectly.  Blankets in order, animals in their places, each parent has to give a kiss, and then bye bye's and blown kisses at the door.   I am okay with this night time routine.  It is what comes next that makes me want to pull all my hair out.  
   The Excuses begin.  Here is how it has gone so far tonight as I am sitting her typing this.  First, Jae says she has to pee pee.  I let her go because we are trying to get her to stop peeing in her night diaper.  Then, I have to re-tuck and Daddy has to come back into the room to kiss her.  He tried to protest this request tonight and Jae was besides herself carrying on, so Daddy caved.  Then, Kaden claims to have to pee pee.  I lecture him about lying and he just lays his head down and gives up......UNTIL he thinks of his next idea....."Poo Poo, Mama.  POOOOOO POOOOO!"   I ignore this and Daddy goes in and tells him to lay down and that Mama is asleep.  Now, I can hear them talking and laughing in twin language right now, probably plotting their next stale tactic.  What will it be next, will they pull the old, "Agua!  Agua!  MAAAMAAA, AGUA!!!"   Another one that they try frequently is kicking off the covers and then saying "Uh, oh,  Oh no," and crying it out until they get us to cover them back up. Sometime they sacrifice their snugly.  Sacrificial lamb takes on a new meaning her.  Her little lamby gets rocketed out and then she screams just so we will come in and give it to her.  Kaden has been known to do the same with his little Giraffe.   Sometimes they try to request new never slept with before toys or animals, as if their cribs are not crowded enough as it is.   That's right, I said cribs.   This bedtime game is so hard that we still keep the twins in cribs.  I think I am the only mom I know that still has kids this age in a crib.   I need to get this bed time chaos fixed by the new year, because that is the date we have choosen to start them in beds.  I have no idea where to start with this.   I am completely open to any ideas on this one.  They share a room, fight bedtime, and ometimes they play across the room in their cribs for an hour before they fall asleep at nap time and bedtime.   This will definitely be a challenge.  If anyone has ideas for me, let me know.