Mystery Pipes (and 2" or 1.5")

Hi,

I am moving my pool pump and filter about 15 feet, so I am starting to plan for extending my plumbing. While doing so, I came up with a couple mystery pipes:

• One (marked "A" in the picture) is 1.5" and always seems to have a little water in it, usually above ground/pool level. Today, the water in it was about 12" above ground level.
• The other (marked "B" in the picture) is a 2" that has a couple 90s and is capped.

Wondering what these "vent?" pipes might be for. They aren't under pressure and are independent of the intake or return lines. Wondering if I should cap them off under ground, where they are now, or extend them with the rest of the plumbing to the new pump/filter location.

Next question. intake and return lines are about 50' of 1.5" PVC with lots and lots of 90-degree elbows. I want to eliminate as many elbows as I can, straight pipe or 45 sweeps when necessary. I can access about half of the 1.5" PVC, but the other half is under concrete. Should I step up the 1.5" I can access to 2"? Would I have any increased flow, or would the remaining 1.5" under the concrete choke everything down regardless?

Any other tips, like 11" of straight pipe before the pump, etc.?

Thank you!
Jon