Doh! I figured you either had LoopMIDI installed or would install it after I mentioned it since Nuked-SC55 prints this to the console window without it.
No midi input
ERROR: Failed to initialize the MIDI Input.
WARNING: Continuing without MIDI Input...
My bad. 😮
Anyway, just install LoopMIDI, then it should be available in CoolSoft MIDIMapper while you have it running.
I haven't tried any of Tobias Erichsen's other software, so can't comment on those. Before Nuked-SC55 I used Patch93's SC-55 soundfont with VirtualMIDISynth in Windows XP, then switched to SoundCanvas VA when I started using Windows 10. Nuked-SC55 is the most accurate sounding software option though imo.
I was excited to try Trevor's soundfont when I first heard about it, but was a bit disappointed that the reverb is baked into the samples. Even after trying v1.3b, I still preferred the sound of Patch93's SC-55 soundfont. Still, was a cool project to discover.
I haven't tried Arachno yet, but read that it sounds very good too. I mainly use SGM-V2.01 or S-YXG50 to play certain mids that I prefer over using SC-55 for. For example, Club Paris sounds cool through the Yamaha and I really like how Bittersweet Reminisce (Image of Hero Remix) sounds with SGM-V2.01.