First, a few points to keep in mind no matter what method you use:
* You can't change things quickly. Children thrive on understanding expectations.
* Your children are being tossed and tumbled around right now with at least three different parenting styles/strategies. You, your wife, and her ex. On top of that they are being taken to a variety of activities and probably have no idea what life holds for them in the next hour, nevermind the next day or next week.
* Whatever advice you receive is going to be a product of personal experiences. For instance, almost half of my children fall on the autism spectrum, near aspergers level. Understand the suggestions, see if they apply, and discard those that don't.
With that in mind, I've found that children of all ages respond well to
* Gradual changes
* Clear expectations
* Consistent enforcement
* Discussion/comfort/attention
So let's take the example of specific rowdiness. I can't tell my children, "stop roughhousing" and expect them to stop doing whatever it is that's annoying me, I need to either tell them a specific thing they have to stop, or I have to repeatedly define what "roughhousing" is and never change that definition.
It's far easier to focus on a specific activity than a general one.
So I might be saying, "That's too loud! Please don't yell inside the house," which gives them a boundary that's clear, without vilifying them or their behavior, merely instructing them as to when it's ok and when it's not. If they want to yell, they can go outside. (incidentally, screaming and shrieking are right out - I need to be able to quickly tell the difference between pain and play, so there are a few sounds I just don't let them make on a whim, plus, wow, shrieking hurts! I know parents that allow their children to shriek and I'm convinced they've damaged their parents (and their own) hearing enough that they simply can't hear the shrieking as painful as it actually is). Anyway.
If I introduce a new rule, I only verbally reinforce it for a week or two, and I only remind them occasionally, even if they continue to misbehave. It can take that long for it to sink in, and generally kids want to please adults around them, but it's easy for them to get caught up in their play and forget. At any rate, I don't take away privileges or apply punishments for some time after I introduce the new rule. After a time, though, I start telling them the consequence for continuing to break the rule.
"That's too loud! Please don't yell inside the house. If you keep yelling, you're going to have a time out."
"That's too loud! Please don't yell inside the house. If you keep yelling, you're going to have a time out. You have two more chances."
"That's too loud! Please don't yell inside the house. If you keep yelling, you're going to have a time out. You have one more chance."
"That's too loud! Now you get to sit on the stairs."
If your children aren't used to time outs, you might have to keep putting them on the stairs. In my house I escalated the punishment. "If you can't sit on the stairs, I'm going to put you in bed" then three chances later they end up in bed. "If you don't stay in bed I'm going to hold you in my lap." Then three chances before holding them (gently!) in my lap for several minutes. It usually only takes once or twice of holding them before they stop getting out of bed, and only a few times of having to go to bed before they stop getting out of time out without being told. But there is a clear path for escalating a punishment, and they don't like the options, particularly when they understand it's a punishment.
The expectations have to be clear. While I already discussed the difference between roughhousing and screaming as an expectation, another issue is making sure they understand the bar. "If I can't talk to your mother in this room because you are too loud in that room, then you will be in trouble." They know there's a level of loudness they can achieve without triggering a problem, and they know there's a good reason for the rule. It may take some time for them to figure out what that means objectively for them, but you need to remain consistent about the rule. Try not to keep changing what level of loudness they can have based on things they don't know, "I've had a hard day at work, can you be more quiet?" While you can have rules like that, you really should try to cut back on the number of rules they have to follow. If you have 20 different rules for how loud they can be (you have to be quieter when I'm watching a movie with speakers vs headphones, or when I have guests over, or, or, or) then they'll have a hard time meeting your expectations. But they can follow a few different rules for each type of activity, you just have to alert them when the situation changes. "Ok guys, mommy's taking a nap, and we have to be extra quiet. Do you want to go outside, watch a movie, or read some books?"
Lastly, address their concerns. If you don't want them interrupting you and not listening to them, you have to avoid interrupting them and not listening to them. If they know the rules and are disobeying them more than you think they should, pull them aside (away from the activity), get down on their level, and ask them if they're having a hard time following the rule and why. You might be surprised at the issue that they believe is preventing them from obeying, and you might be able to help them resolve the issue, or at least understand it. Of course you can simply reinforce the rule with a reminder of the consequences, but seek first to understand, then to be understood.
I can reason with my almost 2 year old despite his limited verbal communication because I do often get down at his level and chat with him. He listens and understands, and he is learning that certain behaviors aren't acceptable (these days it's hitting).
At any rate, here's some thoughts and ideas, and I hope it gives you something to try. Children can adapt dynamically to their environment, so you can have expectations that their father and even mother don't have for them, as long as you yourself are unfailingly consistent. You don't need to accept, "Well mom does..." or "Dad doesn't make me...." - a simple, "That's true, and when you're with them you get to follow their rules, but right now you get to follow my rules," is sufficient.
Good luck! It's an adventure, but it will be worth it.
Well, weather permitting. This is usually only a real issue during summer break though, since they are 7 and 10.
