[cypher]

Some squeaking is normal but you do need to keep a close eye on them to make sure it doesn't escalate in fighting, if it does then you would need to separate them.
If one is a lot more reluctant to come out it can be a sign of bullying so keep a check on that ones well being, size in particular as often as a result of bullying one will not be getting enough food.
A little nipping or nibbling at first is quite normal, they usually grow out of it unless it becomes a territorial behaviour in which case they usually only do it in the cage & not during out of cage time.
It's very early days so they will still be settling in but pairs can be quite challenging to keep together without them falling out as they mature so you do need to be watchful with them.