To me this sounds a bit like Lightning Network, where you send back and forth transactions representing the current channel state that can be published at any time and include a lock time so cheating attempts can be detected and mitigated if checking in often enough.

If it's implemented the same way as in LN commitments, it should work fine. By resending a new transaction from time to time, it can also account for mining fee fluctuations and with long enough lock time it won't require a watchtower or checking in manually way too often.

I don't think the 'escrow address' is really needed; the commitments can send money directly to the kid's address (with lock time on the utxo though), just as in LN.

What I think would make more sense implementation-wise (as also suggested in the other thread); would be simplifying to e.g. a shellscript that creates those transactions which can then be submitted with any client you want. The commitments can be transferred however secure way one prefers, which can be PGP encrypted e-mails, encrypted messengers or whatever. If this is really for the sake of inheritance, it can't be based on a phone app that itself (and / or its servers) might not be around by the time someone using it actually dies and wants to inherit their coins.

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Off-topic, but not sure if you need to cryptographically secure your BTC from someone you want to inherit it to. Like, this whole mechanism (over e.g. leaving behind an instruction on how to just get access to your wallet(s)) is to make sure they don't try to steal your coins before you die. Not sure I'd want to inherit my holdings to a person that I feel could try stealing my possessions.