Hello! Glad to see more people getting into the game. Now, for your questions...
Whether or not you get the Golden Pack depends more on what difficulty level you're playing on. If you're playing Normal or even Hard, you shouldn't really need them, as Reeking Boxes are cheap and readily available on Normal, and SpotPass teams are available for grinding on Hard. Golden Pack is very helpful for Lunatic/Lunatic+, but since this is your first game, I doubt you'd be jumping up to that so quickly.
The Scramble Pack is okay, but the conversations are the important part from it, and you can see videos of all the Scramble conversations on Youtube (look up justonegamr's channel).
The Future Past one is very good. It's got great conversations between fathers and children, the backstory additions are good, and it's difficult enough to be a challenge. I'd highly recommend that. However, I'd say wait to buy it til you've recruited some of the children characters later on, since it won't be worth much to you until then anyway.
For packs you didn't mention: Lost Bloodlines and Smash Brethren are both great packs to get. Lost Bloodlines 2 gives the Dread Fighter class (a male-only class), and Lost Bloodlines 3 gives the Paragon skill (which doubles exp gained). Smash Brethren 2 gives the Bride class (a female-only class), and Smash Brethren 3 gives the Iote's Shield skill (which negates super-effective damage for fliers - not essential, but nice if you're new to the series).