Some of these are excellent solutions. If only there were a problem.

Banking is credit arbitrage. Nothing else is banking. Taking deposits and providing services is not banking. Creating a coin is not banking. Overcollateralization is silly. You put $2 in the bank and get an account for $1, and the bank puts your $2 in a vault. That achieves what for whom? Whatever it is, it ain't banking.

Credit - people with credit (aka investors, some of which are banks) financing the creation of the products that will be sold to repay the financing - makes the economy go 'round. If a "bank" isn't extending credit, who the f*** needs it? Banks are regulated and, when necessary, bailed out because banking is an essential service. Crypto science projects are not an essential service. Because they aren't banking. Because they don't create money in exchange for creditworthiness.

When someone can show me a (non-crypto) project - you know, like a home improvement or a new power grid - that was financed by crypto and could only be financed by crypto, I'll believe that crypto has something to contribute to banking. Until then, crypto may offer a better way to move money, and stable coins may have a useful role in that process. But just as market making and mint/redemption are the same thing, creating and destroying tokens for fiat is the same thing as changing the ownership of fiat reserves. That problem hardly calls for so many solutions, each one harder to understand than the next. Rather, national central banks will create stable coins backed by the full faith and credit of their countries and "pegged" to a rate of change in the GDP Deflator, and that will be that.