The two engines are mechanically very similar, in some cases using the exact same block & head - however - there were significant differences in the engine management electronics & sensors - you might need the intake manifolds & sensors off of the 1.8 as well as the ECU & harness.
There were also differences between the early & late 1.8s as well - I'm not certain which years had what, but early 1.8s had a separate ignitor module and late 1.8s had the ignitor in the coil packs - you'd probably be better off with the later ECU & harness. One way to tell which you have is to look at the coli pack connectors - you want the 3 wire ones.
Edit - I'm at my desk now - so I can look stuff up.
'96 & '97 had the separate ignitor module, '98 has the ignitor in the coil pack, which is how the 2.0 is set up. The 2.0 uses a different cam position sensor to the 1.8, the 2.0 has the MAF sensor out near the air filter housing, I'm not even seeing it in the 1.8 drawings, it's most likely a part of the throttle body, the EGR & IAC are different.
If you can get the intake off of the 1.8, and since you're looking at a '97 the ignitor & coil packs, it might be "do-able"