serious eating mix up issues!

So I have three wonderful amazing pets-- 2 cats and a dog, I just recently got the second cat and that has messed up the whole meal time dynamic a lot!

Problem number 1: My dog is a lab so he eats everything, including my cat's food. 

Problem number 2: The cats.  They eat each other's food.  I am concerned that one will get too much and one will get too little, resulting in weight issues. But do cats know there food limit more than dogs?  My dog is a bit overweight.  If left to  their own devices will cats eat so much that they get fat or is that just a dog thing?  

Problem number 3:  My new cat eats my dog's food.  And he seems to have an extremely sensitive stomach.  When we switched his food it resulted in bad bowl movement issues.  And now it is happening again.  It could be because he is eating my dog's food, but also maybe because my two cats are on different foods.  My one cat is 1 years old so he gets adult food, but the kitten gets kitten food (but is also eating the adult food).  

Problem number 4: Also I want to transition my 1 year old cat to adult food but he keeps eating the kitten food! ugh!!

Sorry this is so long but I would appreciate any ideas! Am I making a bigger issue of this than it is?  Should I just not be so uptight about them eating each other's food as long as they are all eating?  Is it detrimental to their health if they eat the wrong food?  

Anyways, thanks for any advice/input you all have! 

I'm really not an expert on this, but I do have a little experience with cat foibles in general.  Dog food is not good for a cat.  It won't poison them or anything, but the nutrients aren't right.  If the cat is eating a normal amount of the proper cat food, he'll be fine, but you do have to watch out for weight gain.  YES, cats will also overeat.  Not all of them, but many.  Hekitty (my cat) will eat her kibbles AND as many Temptations as she can beg or steal.  She's looking like a furry football, is now on a diet, and is driving me mad.  It isn't easy, but it can be done.

You may have to feed all of the animals separately for a bit,  At least until the kitten is ready to transition to adult food,  This is, I know, a real pain, but it may be necessary for the health of your animals.

As for when to switch from kitten to adult foods, I've heard so many answers, from 6 months (WAY to young, in my opinion) all the way up to (this is what I did) 18  months.  The good thing about that is, your cat reaches pretty much full physical growth and maturity before the transition.

Hope some of this helps!  Good luck with your blended family!

Cats when switched to a new food suddenly will usually have a bought of diaherra until they get use to it. That is why they recommend a slow switch over a week period with a mix of old and new food. I may be wrong but I don't think that them eating each others food is much of a problem unless they are on a special diet. It may make the one on regular food gain a little extra weight. In my experience most cats don't eat to much unless they have had a problem thinking they wont get another meal.  

I feed one cat in back room, one in kitchen, and dog in kitchen. All feedings are timed, no free feedings, everyone eats canned food and finishes it right away! They all get wet food!

My lab is the same. In fact, she PREFERS the cat's food, and would go out of her way to try and get the food. At first I put Tucker's cat food behind his scratching post/condo so Hershey couldn't get it, though that was a pain to work around so now he gets fed on a higher surface (one of those plastic storage drawers on wheels). So that would help your first problem.

The next problem where your cats eat each other's food, you've got a couple options. First, you could transition them to eat the same food. Kitten food won't hurt the older cat (but he'd need less of it), or you may be able to find a really good quality 'all life stages' food. But you have to be careful with that since rarely is an all life stages food actually suitable for all life stages. It would need to be high protein, low carb. Personally, I like Petcurean Go! Fit+Fresh, from what I've seen, it meets kitten and cat needs. Plus you can feed less of it, so it may be easier to feed it in one sitting.

Alternatively, feed them separately, and take their food away after so long (say 30 minutes); you can include the dog in this, that way the dog food isn't out for the kitten to steal. After a while they'll learn they have to eat within that time frame. Then just feed them in meals instead of leaving the food out

Thanks for all the great advice everybody!  

That's what we're here for, Darlin.  Oh, and celebrating the happy times with you, and holding your had through the bad ones, if you need it.  This really is a community.  You know what they say, it takes a community to survive  your cat.