My son will be 7 next month and my daughter will be 5 in October. Here is our routine.
At 7:30 the kids are sent upstairs. If it is not bath night, they have to change underwear and put on pajamas and come back down. On bath nights, they get undressed, go potty, and get ready for a bath.
Once they are back down, we clean up toys. Then we drink milk or water. Each child gets 1 book of their choice (unless it is really long and then we only read part of it). If we are really running late, we may only read 1 book (and whoever was the leader for the day gets to pick it). After books, we have hugs and kisses. Then we go upstairs to brush teeth and go potty one more time. While one of them goes potty, the other brushes teeth and vice versa. The kids get in bed, we tuck them in, dim their lights, and say god night. We do not lay down with them.
If one of the kids gets up or calls us upstairs without a good reason then he/she gets counted. Once he/she gets to 3, we take away a stuffed animal for the night. They almost never get counted at all, much loess to a 3! Good reasons for getting up include being sick, really having to go potty (you get counted for not really having to go or only making a drop or two), or some other real problem.
About the leader for the day: my son is the leader on odd days and my duaghter is the leader on even days.
Do your kids use nightlights? We installed ceiling fans in the kids rooms that have a dimmer switch and a remote control. We dim the light low so that it gives more light than a regular night light but is low enough for them to sleep. They sleep with their doors open and the hall light dimmed low too.
Have a set time the kids need to be in bed by such as 8:00. Nurse the baby before it is time to start getting the other kids ready so you won't hve to interrupt your routine for that. If you have 2 bathrooms. have your husband take 2 kids to 1 BR while you take the other kids to the other BR. That way, you only have to help 2 kids brush teeth and go potty. Since they will have already put on pajamas and read books, all that is left it getting in bed and tucking them in. You can each listen to prayers for the 2 kids you were responsible for. Make the rounds to kiss everyone good night. Do not lay down with them. You may have to gradually wean them off but the sooner the better. You and your husband can alternate which 2 kids you are responsible for each night so that you get to hear everyone's prayers at some point during the week. On the nights your husband is not home, it will be a little crazier but still doable. You could make a game of getting teeth brushed (properly) and getting in bed first. Maybe you could put the 1 year old in her crib to listen to music while you tuck the other 3 in.
Good luck!!