I'm not sure if this scheme is actually great. It looks overly convoluted to me and frankly I don't know why it's that much layered, to be honest. @satscraper could you explain what kind of attack vectors you try to remedy or your reasoning with such a multi-layered approach?
Then indeed more points of potential failure are introduced, at first glance. The hardware keys would need copies otherwise you're pretty much screwed if you've only one and this sole one gets damaged, stolen or lost.
(OK, after actually reading SEED storage on digital media., you use three hardware keys from Yubico, so it seems there's redundancy.)I hope you've a hell of a good instruction manual for those who are supposed to inherit your stuff should something bad happen to you. And don't forget, you know your scheme well enough now, you constructed it. Years later and without much use, this could change as human memory is a fragile and changing thing. For those not involved in your scheme, instructions would need to be much more elaborate.
Don't get me wrong, I'm not per se against digital storage but I'd like to understand why such paths are walked and to what problems it's aimed to be a valid solution. People need to understand why handling such precious data like mnemonic recovery words and/or mnemonic passphrase on digital devices is potentially dangerous and how to do it safely.
And don't do fancy and complicated procedures just for the sake of it and because you can. There should to be a clear purpose and need for every layer of protection!