After you have installed iphoto I would recommend that you return .plist to correct value. It only needs to be 5.1 while installing. IPhoto will run fine once installed with it at 5.01.
I have it installed. Only thing I notice is when it updates library, it doesn't 'see' all of my camera roll, only photos that are in albums. I had photoalbums+ installed from Cydia, however I have found it simpler to remove this tweak and just have a single album called 'iPhoto'. (TBH I never really found any benefit to having my Photos organised into albums. I don't sync photos with iTunes but just save them to my HD as if from USB device, and sort them by date there)
Then I can move photos to that folder for editing but keep the original in camera roll. With Photoalbums+ the photo was moved rather than added, so I was losing the original when I edited it.
It remains to be seen whether i will use this app much. I use Hipstamatic a lot, and prefer that method of adding effects by using different 'lenses' and 'films' BEFORE taking picture. It takes some lovely pictures if you experiment with it.