Just use Mini vMac to make disk images and write them to the USB floppy using RawWrite. It will write HFS disk images created in Mini vMac on modern versions of Windows no problem.

Also, if you're going for System 7.1, I suggest System 7.1.2 from the Legacy Recovery CD, as an upgrade to 7.1.1, (aka. System 7 Pro), which you can also get from the Legacy Recovery CD. Its the last member of the System 7.1.x family and it runs a later version of Finder (7.1.4) than System 7 Pro, which can allow you to run some software that says it will only work on System 7.5.x