1. "The customer is planning a maintenance shutdown in September 2016."
2a. grasp = understand, comprehend
2b. acumen = sharpness, intelligence, quick-wittedness
3a. "Let's get it going" is a slang way of "let's get going" which means "let's leave, let's begin moving"
3b. "Let's get started" also means "let's leave" but more generally it means "let's begin" (a game, a meeting, a task, etc.)