I just got a "new" iMac (at least for me), and I'm wondering what's the best way to move all the different files? I currently use Ableton Live Suit 10, but will get Ableton Live Suit 12 for the new iMac. I have a couple of questions below

1) The projects files are OK to move I guess, but I have bought many sample packs over the years to Serum etc. Must I go over each folder manually or is there a better way?
2) I also read that you can pack the project files with all the sounds, but that would probably create a lot of duplicates and take up extra space?
3) For the plugins, I have kept most of the installation files (I think). Or is there a good way to move these as well?
4) Since I will get a brand new Mac in 3-4 years, I think I will put the whole sound library etc. on and external hard disk (LaCie Rugged USB-C) to avoid having to move everything again later. Is that a good idea, or will it make things slower?
I want to make this "perfect" this time around, so if anybody has some other tips I would really appreciate it!