Don't feel guilty about locking her in a room while you're eating. It may help with the meowing if you eat at the same time though. Just serve her food in another room and shut the door before going to your own dinner. That way she doesn't feel like she's missing out on something. She may even get used to it and not want your food too eventually.

Other tips...

If she wakes you up at 3am she may need to sleep in another room for a while too. She may eventually get used to sleeping in, she just needs a schedule reset.

If she gets up on counters and things she isn't supposed to you make sure you have surfaces that she CAN climb on. If she continues to jump on the counters too you can discourage her with a squirt bottle full of water. Be sure to praise her when she's being good too though!

Make sure you have lots of scratching posts available or your furniture will suffer. If you catch her scratching furniture, gently move her to the appropriate scratching post. Put some catnip on it too! The idea is to make the post more attractive than your couch. If she still has issues with this, there are little nail caps you can get that work like press on nails. They make the edges blunt so she can't damage anything with them.

Cat hair is your life now. There is no getting rid of it all. Just do your best.