QUery related Excel formula

Hello Everyone, 

Heads Data 2 shows the same information as the original Heads Data 1 however:

I have 3 question :

1 --  Two employees are missing. Who are they?

2 --  The job title of one employee has changed from 'CRA - 2' to 'Senior CRA - 1'. Who is it?

3 --  One employee has got married and their surname has changed. Who is it?

(Note - You can see all questions in TASK sheet)

Please help

Here is a attached file