There was one particular guide online that basically rearranged the sequence of events to maximize the number of X.0% occurrences (because those are when you can tell if you missed anything due to rounding/display) that does a far better job than the printed guides.
Squeenix social media already confirmed that PS4 version is cross-save/cross-trophies.
Anyone notice on the Trophy lists that FFX and X-2 now list "PS3 PS4 PS Vita"?
Squeenix social media already confirmed that PS4 version is cross-save/cross-trophies.