I just installed IK Multi Media Hammond B3X + Leslie Collection. It's certainly not free, but it's $180 with a discount code I found.
It is the closest thing to a real B3 I have ever listened to.

This is the main image, but the are other useful images to use.
[Linked Image from i.imgur.com]

I don't have a waterfall keyboard, but I assume I can connect three keyboard controllers and play everything, using an expression pedal and a foot volume control.
I never learned to kick the pedals on a real B3 anyway. To dyslexic for all that monkey motion...lol

Anyway I highly recommend this software as best in class.

Billy


“Amazing! I’ll be working with Jaco Pastorius, Charlie Parker, Art Tatum, and Buddy Rich, and you’re telling me it’s not that great of a gig?
“Well…” Saint Peter, hesitated, “God’s got this girlfriend who thinks she can sing…”