I don't know about the memory useage. Are you using Fu_PerformanceFu or something similar that tells you just how much each mod is using?

I've had that problem with the empty buttons as well. I found that I could make it work by using Button Edit to change the button type to macro or whatever. I don't know why sometimes it prevents you from dropping in a spell or macro. You might check the Trinity forum at WoWInterface.