The Leo Bodnar Button-Box is a USB-based simulation of a keyboard, driven off discrete inputs to mimic key-presses. It's advertised as Windows/Linux compatible, so that should be no problem.

The Universal G-Code Sender is a cross-platform Java application, advertised as Windows/Linux/RasberryPi/Mac, so that should be no problem.

Joy2Key takes game-controllers and interprets demands into key-presses. There is a linux flavour of this available, as well as alternatives from a quick google. So this should be no problem.

It will take a bit of effort to hook all three together, but I have no experience of any and can't advise further. I'd suggest - assuming you have no spare desktop machine - dual-booting your Win7 box and installing one of the common flavours of Linux. Which leads me to...

How easy "is linux"? Things have moved along massively since I was a lad (some 30 years ago when I first looked at Linux). Most distributions come with full-fat graphical installers and default to a full-fat Linux UI with lots of capability built in from the start. In true linux fashion you will find yourself at the console level pretty quickly installing packages and scripting, but there's generally a lot of people who have already done the things that (I) expect to do and are only a google away. It's a personal thing, but I'm constantly pushing away from Windows (trying to think... I think my only Windows box now is supporting my CNC mill - just because I need that for UCCNC. Every other box I have is either Mac, Debian linux (CNC lathe) or Ubuntu (my initial moves into Linux). Oh, and several RaspPis that are also flavours of linux.

My advice - go for a low-cost dual-boot trial to find your feet.