Some of this may be guesses so keep that in mind.

1) This is on the pressure side of the pump so it may have been a pressure side cleaner.

2&3) One is from the skimmer and the other main drain. My guess is the main drain has the valve but it could either one.

8. That looks to be the filter backwash line. What type of filter is it? It may just need to be backwashed.