via Bob McKenzie tweets,

On Kovalchuk, agent can agree to contract terms with new team, new team can agree to trade terms with NJ, NJ signs Kovalchuk and trades him.

Kovalchuk cannot come off the NHL's Voluntary Retirement List unless he signs with NJ. Therefore, the need for a sign and trade.

Technically, Kovalchuk cannot "sign" contract until July 1, but there's really nothing to prevent everything else happening before that.

So in answer to many questions, no, 2017 draft picks cannot be in play as part of any Kovalchuk trade and expansion draft total non-factor.

Also reasonable to assume Kovalchuk not interested in being part of NJ rebuild; he's returning to NHL for immediate/legit chance to win Cup.