Inferring anything from this is like concluding that if a guy asks a woman out, she must want to leave her current boyfriend.
It doesn't cost the Nets anything to make this request, and it may make sense even if they think it has zero chance of going anywhere. They may just want to set the table for a relationship with Doc later, or send a signal that they are willing to hire a top-tier coach (This is just like the C's interviewing Nerlens Noel at the combine.)
Or, the Nets recognize that this season has lots of uncertainty, and that for a variety of reasons having nothing to do with Doc, things could change dramatically over the next month. It benefits the Nets to move first given how many other teams would want to hire Doc too.
Once again, Doc has done or said nothing publicly indicating that he doesn't want to return. Danny has said Doc is coming back. Repeatedly.
Seems like a tempest in a teacup to me.