Golfy to answer your question on #449
B777 FCOM 4.20.17
"Pushing either TO/GA switch activates a go-around. The mode remains active even if the airplane touches down while executing the go–around."
However and this is relevant in a GA immediately after touchdown
"The TO/GA switches are inhibited when on the ground and enabled again when in the air for a go–around or touch and go."