George,

No, it doesn't matter if the programs that you connect to are 32-bit or 64-bit.

loopMIDI and MIDI-OX happen to be 32-bit programs, sure, but their job is just to steer the USB keyboard MIDI signals in and out. It's the signals you want.

So, for example, in BIAB (either 32 or 64) you're configuring the MIDI input device to be what you created in the loopMIDI program.
In my case, it's "loopMIDI Port 2".
In Reaper, the MIDI input device that I created is called "loopMIDI Port 1", and for RealBand, it's "loopMIDI Port 3". You could add more if needed.

MIDI-OX takes the output from my Nektar LX49+ and then sends it to all 3 of these "pseudo-devices". Likewise with the UM-ONE device, that's a USB device on my Roland E-20 keyboard. It's probably harder to describe it all, than it is to set it up! Good help files are included.

Net effect is that I have both keyboards available simultaneously to all 3 programs. Plus, those monitor lights and log are handy troubleshooting tools.
Now if I can only get good at playing, LOL! Having fun learning.

Jerry
2019 BiaB Megapack (634), RB 2019 (Build 4)
Reaper 5.983 x64, Audient id14 USB interface, Voicemeeter Potato 3.0.0.8, Nektar LX49+, Roland E20
i7-6700K Skylake desktop, 64bit Win10 Pro(1903), 32GB ram, 512GB system SSD + 2TB data SSD