Please tell me about any other airline's elite programs where they will let you displace someone else so that a top tier elite and their family can sit together.

This is not a published benefit, and not all agents will do it, but if you go up to the podium at the gate and ask nicely, the agent may be able to seat you all together (if available) in Even More Space with the fee waived because you're a Mosaic. But again, this is not a published benefit, and gate agents are not obligated to do this although some of them will.