The 1.8 and the 2.0 heads should be the same or very similar - depending on which vehicle the 1.8 was used in, it's actually the same part number - have you tried fitting the 1.8 cam sensor to the 2.0?
Looking at the parts manuals - the 1.8 Esteem uses head #11100-65G00 & cam sensor #33100-77E20, the 1.8 SideKick Sport uses head #11100-77E00 & cam sensor #33100-77E20 (same cam sensor on both engines), and the 2.0 Vitara uses head #11100-65G00 (same head as the Esteem) and cam sensor #33100-65D00.
Going from memory the two cam sensors use different technology - one is a reluctor syle pickup and the other is hall effect, so unless you're planning to swap the ECU & harness, I think you need to reuse the original sensor.
Something else to be aware of - a 96 1.8 should have two wire coil packs and a separate ignitor module, the 2.0 all have three wire coil packs, with the ignitor in the coil pack, so you will need to reuse the 1.8 coil packs & ignitor unless, again, you're willing to swap the ECU & harness.