Greg responds...

What's to know? That they like each other? It's not exactly a secret. As to the extent of their feelings... which they've hardly (or at any rate barely) admitted to each other out loud, I think it all depends on how ... intuitive each of the people you listed are and/or how much opportunity they've had to observe Goliath and Elisa together.

I would think that Xanatos, Fox and Puck get it.

The clan, especially Angela and Hudson and Broadway and Bronx and Brooklyn and Lex, get it. (I started out writing Angela only, but as I considered each character, I couldn't find one who didn't get it.)

Macbeth... I don't know. It's not that I don't think he's intuitive, but he just hasn't spent enough quality time with the couple to have the chance to observe. And I think that maybe in "Sanctuary", he might have been distracted and/or a tad self-absorbed.

Mutates... same thing. How much have they seen of Goliath & Elisa together? Derek is, I think, the densest of the four mutates. But I'm not sure any of them have had the observation time to figure it out.