I've done lots of different legacy challenges, including Pinstars, though after the first time I give myself more leeway to change things up. I get bored of being on the same lot.
Anyways, what I was referring to is being able to see your unlocked rewards in the catalog. For instance you get an awesome computer for completing the Oracle career path of criminal.
If you go into the attic (family inventory) where everything goes as its earned, and delete those items without the sim who earned them still being on the lot (because they moved out or died) then it's gone from the catalog.
This matters. Consider the fridge you get from the cook culinary career. If its placed in house by the sim who earned it, they pass on, their heirs move a time or two, oops the fridge bugged out (because technically they don't "own" it) so you sell it to rebuy it for the house. Except you can't. Because no one in the current house unlocked it and now that it's gone the game doesn't remember anymore that it used to be unlocked.
Insofar as the lag I mentioned, that's something purely related.fo the.family inventory. The more full.of junk it gets, the laggier the house gets. Not the game. The house. Cleaning.caches dosen't help with that.
Dez