VMs may not even work on a Mac depending on if the OP has the ARM processor or Intel or if Rosetta 2.0 (or whatever they label that translation layer) to run those VM programs. If any of those aren't applicable one is looking at emulation (while there are similarities, they are not the same and those that complain about the performance hit of VMs will really not like the one with emulators).
Now, there is also CodeWeavers CrossOver (which is really just the commercial version of WINE). It's like Rosetta except it's a translation layer for Windows programs to Mac system calls. Downside to this is there is a higher risk of getting infected with Windows malware as well and not all programs are supported (or they may only support older versions of said programs), but there is a list of programs where users have rated support on the WINE project, so that should give you an idea. Programs like Flexi have been noted on that list as well (version 8.1, I think had a Gold ranking as far as support goes).
As to the iPad, I would just see if there is a way to use something like Teamviewer (or similar program) versus trying to to have it run directly on the iPad hardware. While there may be a dongle that can provide the USB functionality, what computation resources it has, may not be up to snuff.
he virtual Machine inside of the Mac, however, you'd need a computer, not an ipad. The other issue that wouldn't make an ipad compatible is that the SP-540 plugs in via USB, which an ipad doesn't have (as far as I know).
Yes, for VMs would need a like processor and other hardware bits that the guest OS would expect to have, in order to run a VM.
Now, I do believe people have used QEMU(emulator and this goes back to how emulators are different to virtualizers) to run desktop OSs on the Ipad, however, emulation has a harder performance hit compared to virtualization and I highly doubt that they were doing anything intensive with that emulation as well. Probably more about saying that it could be done versus actually being productive with it. But a desktop OS can technically be run on the iPad, just how far that gets you is something else.