Tracy, here's how I see it: With Get To Work and Outdoor retreat installed, there are a total of 43 rewards available. The founder and each of the heirs must have 4 unique rewards, so that makes 4x8=32. These 32 rewards must be unique and can't be shared between them. But the remaining 11, the founder and heirs can share. The exact number of awards available to you may differ depending on the expansion/stuff packs you have installed.
So I think the answer to your question is yes, they can all have never weary as long as they have their 4 unique rewards.
Am I correct?