Seeking advice on keyboard performance setup

HI - and thanks in advance for any help!
My need isnt really complicated, but Ive been out of touch for a few years and dont know the best way to do this.
I nedd an affordable keyboard-based setup, which will allow me to play left-hand bass lines, using samples of my own Fender Jazz bass, along with piano parts and synth parts.
Ive done loads of recording, but gigs on keyboard is a first. Im trying to work out how to use a control keyboard to address the bass samples and either piano or synth, simultaneously.
If I use a laptop, I assume I would need sampling software, piano software and synth software, but how to I control what midi chnnels and/or note ranges these receive? I will probably be using a 4 octave keyboard for the piano / synth parts, and a separate 2 octave keyboards for the bass samples. Im very unclear about what software to use to accomplish these things. Advice very welcome