So, I am happy to announce that www.theqrl.org The Quantum Resistant Ledger is working on this problem specifically. We also have our replies to a number of the questions and statements posed here within our medium publication https://medium.com/the-quantum-resistant-ledger.

A Discussion of Quantum Computing and Cryptocurrencies: https://medium.com/the-quantum-resistant-ledger/be-prepared-for-quantum-computing-era-bb1a9ec6cd35

In regards to the hard fork or changing of signature: https://medium.com/the-quantum-resistant-ledger/peter-waterland-2deed7bdbf65deed7b and https://medium.com/the-quantum-resistant-ledger/wouldnt-they-just-be-able-to-switch-to-some-hash-based-or-symmetric-cryptographic-algorithm-if-bdd99dfa03be

A basic risk and value assessment: https://medium.com/the-quantum-resistant-ledger/the-investment-thesis-for-a-quantum-resistant-ledger-9d335f8cf9ef

Our Solution: https://medium.com/the-quantum-resistant-ledger/seed-investment-strategy-pos-algorithm-updates-3b3854e83a4a

We would love your feedback on our assumptions and development.