gt5879c,
The bend is to transition to the bore angle, which is typically 10 to 13 degrees downward at each end. A fabricated HDPE fitting is much more expensive than a "off the shelf" DIP fitting and probably quicker to procure. It's your choice.
The arv is to help vent the high points in your line. The bore creates 2 high points, one at each end. Some only put one arv on the upstream side, but I always specify 2 for improved maintenance. I suggest manual ARVs unless the utility specifies the automatic style.