Ha ha, you are wrong! The B18C1 intake manifold/head is the bastard step child of the B-series intake manifolds/heads (there are a lot of bastard step childs in Honda motors). The LS/B16A and B18C5 all use the same intake manifold flanges. You could bolt a Type R manifold to your LS head, but the LS cams really wouldn't pull the air to make it useful. The B16A unit would probably be a good compromise.

The B20's are also USDM engines. The early (I apologize but I don't know the years off hand) CRV"s had the lower compression (B20B I believe) engine while the newer (probably '98 or '99+) have the higher compression B20 (B20Z?). I believe all JDM B20's are stamped as B20B's (?) but have the higher compression (I believe). It's been a while since I though/researched it so some of it's fuzzy. I believe all B20's came in some sort of awd/awd-designed car so the stock tranny is useless. If you get really lucky, it might just have a flywheel though. Probably best in the end to go with a lightweight flywheel anyway. You should consider a replacement clutch. It's expensive, but worth doing now. No point in tearing the tranny out 6 months later. Oh yeah, once you get your hybrid running, you won't just be driving it on the weekends. Seeya.