Some layman’s thoughts here… could a system be created whereby users in group B or C could send their small trapped amounts to a single depository address, run by a charitable mining pool/org, with zero or close to zero transaction fee.

Miners in general wouldn’t pick up these low value transactions, but the mining org would know that they were for processing and would then mine those transactions and refund the amount to a Lightning address. So the original user can then use their otherwise trapped funds.

There would have to be some benevolence here from the mining pool/org, (as priority is given to low value transactions from the mempool) but it does mean consolidation of trapped UTXOs, and perhaps a small fee can be taken (so 95% is returned).

This could be seen as a “for the health of the network” and “improving adoption” initiative that bitcoiners as a collective could support.