Imo it’s an overpay, but some of that would depend on what type of extension he signs.

Needs to be more for Bear. A 4th isn't enough

Figured he'd been scratched so much and the irony of an Oilers draft pick

No point in Devils trading 1sts, high end RHDs or serviceable roster players for Miller and the like when Devils already are strongest at forward relative to other areas.
Besides, Miller will be declining by the time Devils are contending meaning whatever massive extension he is signed to will be more of a burden than a help.
Better to look in FA (Nichushkin, Marchment, Palat etc) for whatever current needs Devils may have at forward.

Devils absolutely shouldn't do the Vancouver or Anaheim trades

Devils have to include Jack Huges to get Miller (assuming trade valuation is done by a VAN fan)

That doesn’t get it done for Gibson. The reason they’re open to moving him is that they have Stolarz in the short term, and both Dostal and Clang in the long term to fill in. Blackwood is not of value. A second round pick is worth very little. And the Ducks issue on defense is being undersized (top 2 prospects Drysdale and Zellweger will need to play on different lines). Adding another undersized Dman is the last thing they need. I’d keep Gibby hands down

Bahl, a first, and zacha or wood?

I don’t think I’ve ever seen a Bahl play, but his age/size profile is great for ANA. That value overall feels solid for ANA, especially if it were Zacha. Ducks would probably even need to send a bit more back to NJ if it were Zacha, Bahl, and a 1st