Aside from the fact that I think he's awesome and the fact that I am working on Middle Martin Sibling (who totally calls him Junior, btw) right now, I want tons of plot, k? So we shall start with Eisen.
Eisen has been Alex's best friend forever, so he at least knows of him. I don't know what he thinks of him, but I'm all for Eisen having an antagonist if you want to go that route.
Nick... will be fun in the future. So much fun. With the Alex thing and the despising Dom thing... so much fun. He's also an (extremely) outspoken pro-evo, so yes.
Mal... will probably tell him where to go and how to get there if he is ever a jerkface to her. This is why Mal is awesome.
Carly probably just rolls her eyes at him. Sorry, John. XD
Sam... I don't know. I'm sure there will be eventual connections, however!