Hey guys, quick question, if I have a sim family, make a copy of them and place them in a new town with a new save file, will they keep their careers, skills, lifetime rewards and hidden traits (if any) I searched online but couldn't find anything
Thank you in advance!

I'm pretty sure they will if you package them as a family, but not if you save them as CAS templates.

Yes, they will, if you save them to sims bin. Also, they will keep their relationship within the household (but not outside of it - you need N Raas Mover to move multiple households between savefiles without breaking their relations).
Careers are retained if your new savefile has needed rabbitholes available.

There is just one minor issue with reusing Sims from previous games in new ones: if they acquired special outfits in the old game, like Halloween costumes, bee keeping outfits, scuba diving outfits, special clothes through the magic mirror, costumes from the costume chest for children or the ones they get for playing on furniture, chances are that these outfits will turn up broken in the new save. Overwatch has a fix for the broken scuba outfits, because they can crash the game, but there is no fix yet for the other ones.

That would be NRaas Porter. Mover is for in-world moves.

Porter is great. I make an extended family in different homes, set up bloodlines, relationships and stuff... then pack everyone up. Then when I populate a new world, it's all there! A fanatic time saver when building new worlds or starting new games.

My only issue is that once I lost track where one branch of a family went... Turns out she was on a house boat way off in the edge of the map. Would be great if it had a feature where if you packed 5 families, you could place all five and not just the first one. Or maybe I'm doing it wrong.