If you have a single registry on the starknet side, this can be a single contract instance with no configuration required beyond the user setting it as their resolver. That leaves you with the issue of determining who is authorised to update records on the starknet side, however.
If you have multiple registries on the starknet side, you will need either per-user resolvers on the Ethereum side, or a way to configure the resolver for each user to point to their registry on starknet.
Indeed - and you might consider delegating the ability to upgrade implementations to the DAO, for safety.
It would be good if there was something - preferably integrated with the ENS app.
Ideally the DAO would give a grant to one or more organisations to run gateways.