It's worth noting that digital synths typically limit the number of concurrent notes/voices to, say 16, and then re-use them as it goes along- so you wouldn't be trying to emulate 2 x 91 notes playing at the same time- only 16 or 32 or whatever the appropriate degree of polyphony is.
Can the hardware handle it? The CPU runs at 168 MHz. You are producing samples at 48000 samples/sec, so you have 3500 clock cycles to generate each sample of audio data. Can you get the job done? How good is the emulation? How efficient is the code?
My general feeling is that it's do-able, but I don't know how complex Hammond B3 emulation is.
The design goal would be to have a single note use up say 5% of the CPU, then you can have 16 notes at a time using a maximum of 80%. That gives you some margin so you don't end up with DSP under-runs.