-snip- there is no need to explicitly load a wallet after creation because they are all loaded automatically and selected via the
-rpcwallet="walletname"
option for a specific command. Right?
Right, you'll need to add
-rpcwallet to every wallet RPC if you've loaded more than one wallet, otherwise it'll return with an error:
Wallet file not specified (must request wallet RPC through /wallet/<filename> uri-path).
Try adding "-rpcwallet=<filename>" option to bitcoin-cli command line.