Yes, you can pick any 2 options. Most people will opt for the ones that are most relevant to their jobs, but you can choose them on personal preference.
Yes Dear LUKONDE ZIMBA
You can chose any combination from any 4 optional papers its depends on your personal mind
setup, the relation you mentioned above is good according to me, because i am going to chose P6 & P7 as my optional papers. best of Luck.