This may help.

That engine in the CRX is the 88-91 CRX. It is a D-series engine. That means you can go from say 1988 to 2000 for a D15 or D16 engine (1.5L or 1.6L though the blocks are all the same to mount.) You can go with something like the D16Y8, thats 127Hp and from the 96-00 Civic, so its OBD-II, easier to diagnose maybe, and has the most power of any single cam civic engine in the US. Its an all aluminum block and head and transmission case (the whole tranny without the starter is only 65lbs and its a 5 speed.) There exist 4 speed transmissions that you can fit to it, may be easier for ya. As for other transmissions, Those from an 88-91 CRX are cable clutch opposed to hydraulic clutch, so this may also be easier for you to convert, since you change the cable fitting, instead of attach a clutch master cylinder to the pedal.

D-series use shift linkage...rods to the tranny that go to the shifter inside the car through a small hole.

The F-series Honda engines range from like 2.0L to 2.3L from Accords. Those use cables for the shifting, but these are bigger and may be more of a space issue in the engine bay.

So with some welding, I'm thinking a D-series engine from the late 90s, and the transmission from the 88-91 Chassis would be easier (all D series mount the same and all their transmissions are interchangable.)