Questions About the Gallery and Custom Content

I downloaded some Sims that had custom content but no reference to where the custom content came from. They weren't showing up in My Library until I checked Show Custom Content. If I place these Sims in my game will they have the custom content placed with them or will the game substitute these items to those I already had. If the custom content that comes with them can cause problems though I'd rather delete them, though I like the clothes that the author found elsewhere.

I had a problem with a couple of Sims that came with the game showing up as duplicates. I deleted the duplicates and when I went back to the gallery the Sim I wanted to keep was also deleted. I tried a repair of the game and he did not come back. I found another copy of him in the gallery. I also had some duplicates of a Sim I'd created, I deleted those and the remaining one still appears to be there okay. Is it me or are there still some issues with the Gallery?