Link to my 2017 Redraft: https://www.capfriendly.com/mock-draft/229484
Explanations
Makar to NJD: No explanation needed.
Hischier to VAN: If Makar goes 1st, Hischier doesn't. Can't have both. In my redraft, Hischier falls at #5 to the Canucks. Mercer takes over as the 2C and Hughes/Makar take over the captaincy.
Hamilton to CAR: With getting Makar, the Devils end up not really needing Hamilton anymore. Plus, not enough cap space to pull off the signing. Sent him back to Carolina just because that was the last team he played for before joining the Devils but he still walks in FA, like last offseason.
J. Hughes staying in NJD: Pretty simple. Makar didn't see any regular season action until 2019-20. Assuming the Devils don't rush Makar, they still get the 1st overall pick in 2019, still taking J. Hughes.
L. Hughes to CBJ / Clarke to NJD: Now unlike the past two seasons, Makar did play in 2019-20. And although he definitely makes an impact, the Devils still get the 7th overall pick, keeping Holtz. The same cannot be said for the 2021 season. Instead of getting the 4th overall pick, thanks to Makar, they drop in the late Top 10, hypothetically at #8. L. Hughes would be taken by this point (goes to Columbus as since the Devils drop from 4 to 8, they move up from 5 to 4). So like in real life, done so by the Kings, the Devils use the 8th overall pick to select Brandt Clarke.
Nemec to PHI / Nazar to NJD: Just like the 2021 season, due to Makar and just the rest of the team improving, they go from having the 2nd overall pick to dropping out of the Top 10 entirely. Hypothetically, they drop at #13. Nemec would be taken by this point (goes to Philly because Arizona gets the 2nd pick taking Wright or Cooley and Seattle with the 3rd pick taking which ever one of the two isn't taken by Arizona). So like in real life, done so by the Blackhawks, the Devils use the 13th overall pick to select Frank Nazar.
Summary
In conclusion, although losing Hischier, Hamilton, and etc hurts, they get solid replacements. Obviously Makar being the most notable, replacing Hamilton. Mercer likely becomes a good player in the NHL taking over as the 2C, Clarke has the upside to be a good defenseman in the league like L. Hughes, and though Nemec hurts that deep d-core, Nazar should be a good player in the NHL (might be my bias talking there but I do truly believe that). Overall, the Devils have a bright future by taking Makar 1st Overall, much like in real life when they took Hischier.