Get rid of aliens on the planet

[Lampe]

I have a planet close to my start Planet which i would
like to colonize but at the fields where i can built
buildings, there are aliens (non feeling or something).
I dont want to have them there as in my previous game
i had a planet with aliens on and they started rebellion
so i needed to leave them as vassal. I only want
my human race on this planet. Unfortunately due to my
Ethik im not allowed to kill them. Also the relocation
would cause some unrest to my peoples.
What can i do to get rid of theese aliens? I havent
started to colonize yet. Can i terraform that planet
into an ice planet? Will this kill the aliens and
afterwards i can terraform again into continental planet?

Furthermore: My neighbor is an alien race which is living
on planets which i can not colonize. Im thinking about to
attack him and take him as vassal. 10 years later i could
intigrate them into my system? But than i will get a lot
of aliens in my system which will most likely causes
problems? Can i somehow get rid of them as well?

 

[Gorganslayer]

that formatting doe...

I'm not entirely sure what you're asking about :/

 

[BlackUmbrellas]

If you're ethics forbid you from purging the locals, well, you're sort of out of luck- if that's how you like to play the game, you should consider picking ethics and governments that support that play style.

 

[Lampe]

Yes, but im new to that game. (2nd game now) and we startet small friendly mp game with total 4 players. I cant tell them now that we need to restart because i have choosen the wrong ethics

I'm not entirely sure what you're asking about :/

When im looking into the planet view, there are theese fields where i can normaly built the buildings and where my citizens are growing.
On this planet there are 4 fields where aliens are sitting. Do you know what i mean?

 

[nfmarque]

I do that all the time with pre ftl aliens. Are you militarist? If yes change orbital bombardment to full and park your fleet on their planet until they are gonne.
In early game i scout then i cleanse the area from any pests.