blood
members of a team, company, or organization — usually used in the phrases new blood or young blood
▪ Our company could benefit from some new blood. [=new employees]
▪ We've just added some young blood to the team.
Is it rude to call new employees new blood or young blood?
This is an somewhat unusual meaning for blood. I am familiar with the word being used this way and I don't think it would be rude. Usually it is used to refer to a person and not used when talking to a person. Your examples show the way I would use the word.
I agree with Gillnetter with the exception that, if you are going to directly call someone new or young blood, though not rude, it can come across as very informal and not always appropriate.