Can't help you with #1 or #3, but as for #2, I can't see how Creator would run on the Raspberry Pi because of the memory and graphics requirements. Per the System Requirements spelled out on the "Creator Software" page http://www.simplify3d.com/creator/
System Requirements: Intel Pentium 4 or higher processor, 2GB or more of RAM. Windows XP or greater, Mac OS X 10.6 or greater, Ubuntu Linux 12.10 or greater. OpenGL 1.2 capable system.
I don't know Raspberry Pi very well. I have one, and I have booted it up and done some web browsing with it with a monitor @ 1920 x 1080, and that's pretty impressive. I don't know if it supports OpenGL. But RAM on the latest units is specified at 512 MB. The entire OS runs on a 2GB SDCard. Even if you could install Creator, I can't imagine doing virtual memory swapping to disk with an SD Card. You WILL need at least 2GB, and probably more, of fast RAM. I run Creator on a dual core notebook with 6 GB of RAM and booting Mint 13 / Cinnamon on a solid-state drive. I would regard this as a "good" machine on which to run Creator. (Complicated parts still take some time to render...) An "acceptable" machine would probably need 4 GB of RAM, a decent SATA hard drive, and a decent graphics card (i.e., one that supports OpenGL and probably on a bus faster than plain old PCI).
Sorry, I just don't expect to run 3D CAD-ish graphics applications requiring a couple gigs of RAM (or more) plus sustained 115.2 kbps comms over USB on what's basically a $30 - $40 microcontroller board. This isn't "web browsing" you're trying to do here.
Just my $0.02....