At that point broadcast ticks will become rather bandwidth heavy and might impact on game performance. iOS and Android use a special software depth rendering path which may be negatively impacted by drawing 64 avatars, but we'll see if it does cause a problem.
Really, we want to minimise the number of lots with many objects that are open. Object simulation for entire lots is a lot more expensive than simulating an extra avatar object on an existing lot.
There will be an object limit, but it will work differently and scale with lot upgrade size. It will be much larger than the original game, but will still need 8 roommates to sustain the maximum possible number of objects on the lot.