FCP X Challenges on Yosemite - crashes, incompatible files, using 7tox, waves not being recognized

Hello group. I film and video clips and sometimes have other editors do the first assistant editor cut for me, syncing all the interviews and audio up to the timeline on FCP X. I recently bit the bullet and reluctantly upgraded to fcp x on my 2013 quad Mac Pro. Not only has it slowed down and become crashy since I did the "upgrade", but now I cannot always relink files. My current problem is that my ae is using Adobe Premiere 6 and then exporting xml through 7toX. When the file opens and I try and do the relink, i get the dreaded red incompatible file... This video has 540 files and I'm hoping that someone has a solution. I tried deleting all the bad red files from the Events display, then imported all the files again and they show up, but it still says that the files are not compatible and I know that they are. Does anyone have a suggestion?