Crossword puzzle clue "this answer and others"

Answer, when pointing to this answer, to the question "Which letters answer this clue?"

This answer and others

What the start of each starred answer is part of, for a company that intersects that answer

"Did you figure out the answer to this clue?" answer

Do unto others as you would have others do unto you, but also...

Add vertical line 13 (word 3) and vertical line 3 (word 1) together and enter the answer to the resulting clue on this line

Starting a project ... and what the letters between the starting and ending pairs of letters in each starred answer are doing?

Add vertical line 9 (word 2) and vertical line 7 (word 2) and enter the answer to the resulting clue on this line