As you've already established, you need a six bolt SOHC flywheel for the later "Romeo" engine (the 2000 had a Windsor). You'll also need the pilot bearing for the end of the crankshaft since the motor was originally mated to an automatic. I can't conceive a reason why your 2000 clutch wouldn't work (someone will correct me if I'm wrong)... but if you are going with a new flywheel, at least consider a new clutch disc. As for where to find a flywheel, you might find one at a local wrecking yard but you would want to get that resurfaced...I just looked at Rock Auto and they have some listed that are inexpensive (~$80) if primarily a street driver...or you can go for a steel flywheel for ~$325 from LMR, CJP, AM, or Rock Auto if you are planning on adding HP later. (Part of the issue with your local parts houses is I think the input shafts on the 2000 and 2001 models have different spline counts---not an issue since you are using the 2000 clutch and 2000 transmission, but that may be causing a mismatch in what is now a largely computerized parts catalog world).
Underestimate me, that will be fun.
GREEN WORM RACING--since 1959
These are my opinions...YOU are responsible for YOUR decisions and YOUR outcomes...AND, my not arguing with you does not indicate agreement with your opinion.