I can read. you been trying to compare loki joining to a pair of legs gag.
You said since Luffy invited him, then it's confirmed that Loki will join.
I pointed out that Luffy has asked others to join before, which did not lead to new nakama, so asking alone is NOT a confirmation.
The legs got a gag invite. Guess who else got a gag invite: current SH Brook.
The invites in themselves are not definitive proof of fuckall.
This is on top of all the logistical problems deriving from having someone of Loki's size near the Sunny or indeed on future islands alongside the rest of the SHs. On top of Loki's personality, belief of being the Sun God himself, on top of his worship of Xebec, and on top of him wanting to rampage through the world.