The biggest challenge is not the design you see on the screen. The real problem is how to manage the secret keys (passwords) for the family safely over many, many years.

Here are the three hardest jobs for this "Family Crypto Wallet":

1- Shared Keys (Control for Today): The money needs to be locked in a "shared safe" that requires two out of three family members to agree to open it (this is called "multi-sig"). The design must make sure the keys can be updated easily if someone loses their phone or a key is forgotten.

2- Passing the Money to the Children (Inheritance): How will the wallet work 20 years from now, when the children need the money? It must be simple for someone who is not a crypto expert to claim the assets. It should feel like a simple bank transfer, not a technical puzzle.

3- Working on Many Digital Roads (Multi-Chain): Families hold different coins on different digital networks (like Bitcoin, Ethereum, and the XRP Ledger for fast, low-fee projects). The wallet has to connect to all of these different networks, which is messy for the developers who build it.

I know that multi-chain part is a real headache. It's the kind of complex challenge that platforms like Lumos Core are built to solve.

If you are the designer, I would ask: Which network is the best digital "contract" (digital will) to use for the inheritance part? Ethereum or the cheap, fast XRP Ledger?

Some nice thoughts on designing a beautiful product!