It's the same wallet, data?
This depends on your configuration like -datadir. This can be specified by command line, or something like a registry key value (when you are using Microsoft Windows).
Note that recent versions of Bitcoin Core supports loading multiple wallet at same time.
TL:DR: is the RPC 8332 port active when using the GUI, Vs the Daemon?
Yes, of course both bitcoin-qt and bitcoind supports JSON-RPC.
Edit: My apologies. For bitcoin-qt GUI, to enable JSON-RPC you must specify -server=1 in command line options, or edit bitcoin.conf to add server=1 to it. For command-line bitcoind, JSON-RPC is enabled by default. Thanks for Pieter Wuille for pointing this out.
bitcoin-qtwith the-server=1command-line option (or putserver=1in bitcoin.conf) in order to enable JSON-RPC access. Forbitcoindit is enabled by default. – Pieter Wuille Mar 19 '21 at 19:07