That's looking excellent.
trivial note: I don't know whether you update your comments along the way, or once the build has stabilized, but I just wanted to mention that the ifi_frc.c file still has all the old reference to user_code.c in it's comments.
Another thing I realized when I loaded this project was that your development environment and mine don't match, so it caused a hickup that may trip up first time users (me two years back
You have the CC18 environment loaded under the MPLAB program folder, wheras mine is loaded under the c:/ root. I have no idea if this was a decision of mine, or the compiler default (i think so), or a consequence of me simply "upgrading" last year's install, but it means that when I load your project, two things happen:
1) MPLabs prompts me as to whether I want to keep my old CC18 compiler and Linker folders or use the ones in the project (I say keep the old one)
2) I get a linker error because MPLAB can't find the clib library. I need to go to Build-Options/Directories/Library, and set the path from c:/program files/mplab/cc18/lib to c:/cc18/lib
My only reason for bringing this up is to determine what you, and the likely "critical mass" of users will be using. If CC18 should be loaded under MPLAB then I'll move mine. If this is contrary to the install default, then a "pre-install" readme would be a good idea to prevent (minimize) the initial confusion of new users.
Thanks for all the time you put in.