Metamask would be huge, but saying as someone who builds on EVM chains, it would take a bunch of development on their end to integrate Hive into the wallet, for sure. MM will have to figure out if it is worth it or not. Hive and any EVM chain or even SOL for that matter are completely different beasts. MM is built for EVM chains, but lately has extended to chains like SOL and Aptos because of the similarities in how their smart contract systems operate. I hope to see it happen though.
Coinbase is going to be a whole other thing. Would be good to see it put there, especially to give US citizens another onramp, but I have a feeling that is going to be a big mountain to climb because they will require a shit ton of liquidity, and we don't issue tokens like these centralized ERC-20 tokens can, so that means the funds would have to come from the DHF or from some of the whales to fund that.
My guess is Coinbase is simply nothing more than money. Pay them and they will list...until the delist.