How tough will it be to get everything in Riviera? Options

[Cyath]

Finishing up Yggdra Union now (around BF 44) and I am going to move on to Riviera next...I've heard tell that Riviera's a lot easier on completionists, but how much easier? ^_^

Actually I generally just play through RPGs normally and don't bother too much with the sidequests/extra stuff unless it's really interesting...but for games as good as YU and Riviera I tend to go the extra mile and try to see all the endings/get ultimate weapons etc. Will it be really hard to do that in Riviera? Will I need to S-Rank every battle and hoard TPs like there's no tomorrow?

No need for specific answers...I just want a general "feel" of the game so that I don't play a chapter or 2 and find myself having to restart (like I did for YU) The FAQs aren't that helpful because many of them are spoiler-ridden. :(

[Lord Ryo]

So it was the Skull Stone was it? I thought it was the Dark Matter, thanks for clearing that up for me.

Also, on the items that require a total REP of a certain amount, there are different items you get if your REP is below that number as well. Can you get one item and then if your REP changes during the battle obtain the other item? Or do you have to make another playthrough to get the different item?