Looking for advice

Not sure if this is the right place to ask this...

We, a group of 4 used to live in student housing, all from non-EU. We didn't know each other before starting to live there. The understanding and personal space was there from the start.

Recently one of the guys moved out and a danish guy in his early 20s moved in. Now there are some problems.

1. Often he cooks with other roommates' stuffs.

2. After cooking, he doesn't clean at all and leaves the dishes in the sink for days!

3. Brings his partner almost half the days in a week, occupies the common room where we three can't find any space, even for cooking our meals.

4. Holds party with his friends every Saturday and Sunday without a single message to us. Again occupies the whole kitchen and common room.

As we three are non-EU, we are confused with this behavior. We asked him to clean the kitchen after using it, every time he says sorry, stops his behavior for a couple of days, then agais starts.

Note that we all have individual rooms, sharing the common space and the kitchen.

Our question is, are these normal things or are we just overthinking?