The vacuum advance canister and distributor look the same as '55 Ford 4 bbl. units, except for the tang drive for the oil pump for the '54 engine. I'm thinking a '55 vacuum advance canister might work if it's easier to find.
As far as a kit for the carb, the '54 Merc kits are slightly different, and not covered by the universal kits for '55 through '57 teapot 4 barrels. Pretty sure Mike's Carburetor Parts has the specific '54 Merc carb kits.
Daytona Caburetor in Florida should have the carb kit too.
Sal