Q1: Followed by: A is followed by B. B is followed by C. C is followed by D. Just like that. Followed by refers to that which is being followed and what follows it. Meaning the first thing being first and the second item is second. This could be reversed by saying C follows B. B follows A. A is followed by B. B is followed by C. Q2: This likely means that they will be hiring or bringing in new people to the company or local team. The 'addition' refers to added people or personnel. People use this kind of expression in similar manners, such as a married couple might say "We're expecting an addition" or "There's going to be an addition to our family." to express that the woman may be pregnant.

A1: Yes. Preceding = happening before something (in time or physically); following = happening after A2: Celebrate a new addition*, in this context, means the company has a new employee and they're celebrating this fact. * "New addition" is most often used in family-situations to indicate a baby was just born. --Sorry I clicked the wrong button to answer...was trying to multi-task ;))

A1: Yes. Preceding = happening before something (in time or physically); following = happening after A2: Celebrate a new addition*, in this context, means the company has a new employee and they're celebrating this fact. * "New addition" is most often used in family-situations to indicate a baby was just born.

an addition to our company = a new employee is joining the company. The company wishes to celebrate the fact that someone new is joining them.