The only thing I can think of that Jen had a problem with Dani is the Nick/Dani thing because Dani had/has a BF on the outside and Jen did say something to her about her BF was in an engagement and that Dani broke that up
On the speculation.. ahhh its all in fun.. I know what is coming.. don't forget Dick and Dustin both packed there bags... but wouldnt that be a cool twist though LOL