I think the best way forward is a combination of 1 and 3.
If the team is planning a V2 that does not use USD based stablecoins as collateral for minting agEUR, it makes sense to not allow new minting from the V1 core module. But we want to allow actors to redeem agEUR for USDC because that is what current holders signed up for; The ability to redeem agEUR to USD stables for a fee. This should by itself restore the agEUR peg due to arbitrage. I Also support converting any DAI in excess of SLP liabilities into USDC for this purpose.
However, I think we can implement option 1 in concert with option 3. since we are planning to move to a new model that is Euro based, it makes sense to utilize at least a portion of the surplus denominated in EUROC to balancing the agEUR-EUROC pool, and continuing to support that market to help stabilize the peg, as well as setting the foundation for V2.
TLDR, Allow agEUR redemptions for USDC, but also stabilize agEUR-EUROC using protocol reserves while we transition to V2.
The obvious concern is that there may not be enough USDC to process all redemptions. I don’t think this will be a problem since the protocol is now over-collateralized, and in a worst case scenario where we run out of USDC, we could always convert some EUROC back to USDC in that unlikely emergency scenario.