Most families would use the first name. There is no real relationship with them as there is no common ancestor. But some families might refer to them as cousins or even nephews, though they aren't.
Yes, or you can call them siblings
Nacho (your) cheese
an impasta
call their name and surname together
It is perfectly normal for siblings to fight and to call you or other people ugly. Siblings often say things that they don't mean, especially when they are arguing with their family members.
If it is yours, anything you wish
Aunt
If it is yours, anything you wish
You can call your child whatever you want I mean it's yours.
ur neice-in-law i think
Lily Brother Call Alexander
Flora was an only child.