Well, I've never seen the inlet pipe vented like that and up in a loop - Jabsco themselves supply the pump directly fitted to the bowl pretty much horizontally.
Yes. That is for diagram 2 in the instructions VicS linked to. As the instructions say
YOU MUST select the correct method for the inlet pipework from 2 options and for the outlet pipework from 4 options, according to whether the toilet is above or below the waterline, and to whether it discharges the waste overboard or into an on-board holding tank.
