Two things worked for us.
1) Ironclad bedtime rules.
2) Mom and Dad TOTALLY in sync on enforcing the rules.

It will be rough the first night or two of enforcement. Either mom or dad will be tempted to cave. But get thru the first night or two and it will work.

My friends with 4-ish kids and myself just went thru this phase. My DD would try everything. I'm hungry, I'm thirsty. DH fell for it the first time (got her up at 10 pm and fed her waffles). The first cave teaches them that it will EVENTUALLY work.

We had rules, with slight latitude to allow for times when they are not bluffing. Example:
Potty is ok to get up for.
If you are thirsty, you may have a small dixie cup of water out of the bathroom, but after dinner, THE KITCHEN IS CLOSED!
Otherwise, stay in bed. Mom or Dad will do storytime, prayer, tucking in, etc. (any routine you have will do). Then it's off to bed. Even if you don't go to sleep right away, you must remain in bed and have quiet time. If they call you, listen and make sure the roof isn't caving in or something. Otherwise, bedtime is bedtime.

Any breaking of the rules results in a favorite TV show or toy being 'grounded' from use.

The trick is - they are slick and smart (I knew this because I was the QUEEN of bedtime procrastination as a child). So any caving by either parent, and you go back to the beginning.

It was cool! After 2 days of attempts to procrastinate, she quit trying. She got it! But DH almost caved one time. Then when he realized she was being slick, he kind of got mad! And then he was in sync with me on it. And boom! Two days later, peaceful bedtime.

About a week later, she looked at me at bedtime, and said, "Mom, I'm thirsty. I want orange juice!" All I had to do was look at her, and she said, "But that's ok, I'll have it in the morning."

Good luck! And sweet dreams! (eventually)

Give them the chance to digest that food and they have a new store of energy. Do your happy time at dinnertime or before. After dinner and before bedtime gets them all keyed up.

Sometimes I think the problem is just that people think that all kids are the same and need to go to bed early but that's not true. Some kids are night owls and others morning persons. It does of course depend on your schedule and routine. With me, I'm a SAHM and it's no big deal to stay up and sleep in later. Also, not all children need the same amount of sleep at night as others and it's the same with adults.

I think that it sounds more like your children aren't tired and aren't ready for bed than that you need to start putting them to bed even earlier. Try pushing the bed time later a little bit and see what happens then. Its really going to be a guessing game until you figure out what works for them.