If 1,000 Aliens secretly invaded earth would they take over the earth and start anew?
These Aliens crash landed on our planet long ago, so their technology for the most part is destroyed. The only thing they manage to retained are advanced weapons that can destroy Nuclear Weapons without nuclear fallout occurring.
These Aliens have the special and unique ability to change/manipulate their cellular structure. (They have complete control over their anatomies and bodies of themselves, including skin, nails, fat, muscles, blood, metabolism, nerves, etc., allowing them to freely alter and manipulate them. For example they can grow additional appendages and body-parts, remove them or otherwise manipulate them, in visible, chemical and cellular/sub-cellular levels.)
Each one are in the main Countries there are 10 stationed per country these countries are: Russia, Italy, Brazil, India, France, United Kingdom, Germany, Japan, China, and The United States of America. The other 900 are located in other countries but are meant to stay incognito until they are given the signal.
These Aliens goal are to start anew. To become the apex species of Earth and rule. Their government for now is kind of like a council. The ten in each country share a collective hive mind. Only these certain ten in each country have the hive mind. So the ten in France share a hive mind with each other, the ten in china share a hivemind with each other, etc etc.
They can also reproduce with humans and other Aliens. They take on average 5 months before the child is born and they generally have more than one kid per pregnancy. They can become female or male depending on how they changed their bodies.
Their shape-shifting abilities are detailed enough to bypass highly sensitive eye-scans and voice-scans.
They are basically immortal as they can stay young forever. They can be killed only in a few ways, destroying their brain 100% completely, though few modify themselves to avoid suffering that fate. Completely destroying their bodies is another way. Though keeping them locked up is a option but it is not easy. How would they go about taking over?
EDIT: While pregnant they can not use their shape changing abilties at all. They are basically human with a weak healing factor while pregnant