Original post deleted to prevent further discussion.
I would imagine you can make a character very SIMILAR to the character you want to reference- or just give them the line of another character- and be good with it. Most easter eggs tend not to be very blatant and those would be the best way to go about it. Subtlety is always, in my opinion, so much better than in your face when it comes to such things. Basic rule of thumb though, til you get to be a big hotshot developer and can get permissions from the big boys, don’t mess with anything blatant at all.
Why are you asking us? Ask the people who own the character. Or ask an IP lawyer.
Random people on The Internet can not answer this question.
Fair point!