Hopefully when Travis posts the pre-launch blog post(s) with a lot of the missing details, he confirms that if the game has HITMAN 2 trophies/achievements in the HITMAN 3 lists - if you carryover progress, will those completed trophies/achievements automatically pop or if they would have to be re-completed.
Fingers crossed for automatic popping. 
Tagging @Travis_IOI to increase the chances of getting this answer.
On the topic of HITMAN & Hitman 2 in Hitman 3 do you need to download them in Hitman 3 even if you own Hitman 2 and the Legacy Pack (Hitman 2016) on your PS4? What I’m trying to ask is if you already have Hitman 2 on your system’s save files do you still have to download it again in Hitman 3 or will the transfer be seamless?
The details on how importing H1 and H2 into H3 works, and how to carry over H2 progress into H3 will be known very soon.
That was the case with importing H1 into H2, on PS. But it’s not known if it’ll be the same for H3. We’ll know soon.
Keep an eye on https://www.ioi.dk/ for the blogpost. It’ll also be posted in the OP.
Thanks for replying I guess will have to wait for some clarification 
As this is the last game will the ending cutscene trigger the credits with maybe a cool song licensed?
Hello there @Count.Rushmore ! I hope you’re well. What level is your 47 now?! Been off with other games for a bit. For this question of achievements, some are “reach level x mastery” so do you know/is it known how that is going to work when transferring progress? Are these going to just pop by themselves? Is there a danger of them never being achievable? I’ll have a look at trueachievements.com, too, but maybe you know, or @Euler13. All the best and happy murdering for tomorrow!
Thank you, I’m doing good. Preparing for the launch.
I just hit 3491 of profile level.
Seems it’s unknown how the transferred achievements will work out themselves, I believe those who will transfer their progress will know and share 
I hope those glitches and bugs with unachievable achievements are sorted out for the new game and we’ll never encounter this again.
Also welcome back to the forum
I think you’ve noticed that we had some changes here
Most of us are expecting(/hoping?) them to just pop once we’ve imported our progress from H2 into H3. On Xbox there is 1540 Gamer Score, 1000 GS for the main game (H3) and 540 GS for the DLC, which are the maps from H2016 and H2.
But before any of that can happen, we’ll need the section of IOI’s website that handles accounts and initiating the transfer to go live.