First you wouldn’t want to port this to Win10 IOT instead you would want to start from scratch. I’ve seen the python code and support files, it won’t port well to what is currently available on Win10 IOT.
As for the dev environment you can get Win10 Desktop Preview for free and run it locally in a VM. Then you can also get the community preview of Visual Studio 2015 for free as well and install it inside this VM. There are a few other tools to download too but once finished you can build and deploy to the RPI2 albeit somewhat of a kludge at the moment. I’ve done a few apps already and found it to be very unstable so far not to mention very temper mental to even get an app running on it. It appears to use a trusted computing model requiring certificates to sign code, not fun and annoying as all get out when you just want to toss hello world out there and see it on the screen.
So far mice are all over the place, some work some don’t, no wifi adapters appear to work (I have a ton), no bluetooth and I’m pretty sure it’s only using one core based off the performance I see with some of my simple apps. Check back next year on RPI2 Win10 IOT. 😉