Road to 60 Buff?

[PandaMonium]

I'm not sure they'll get the "Road to 60" buff after a transfer.
Talking of my personal experience, when I created a new character on a preferred world, I got the buff, though my friend that transferred to the same world to play with me - did not.

Same you can see here in the "World Population Balancing Incentives" article - the buff applies to the new created characters on a new (non-existent for now) or preferred world.

Honestly, there's a huge difference between leveling with and without the buff, the difference even more noticeable for crafting/gathering jobs.
I'd suggest you to make a new toon on a preferred world in your Data Center (Primal), which are right now Diabolos, Exodus and Lamia, so you'd still be able to play with your friend but have the buff too. Preferred worlds list changes a lot but you can always check it in real time according to this: "When creating a new character, Worlds in which these bonuses are applicable will be marked with a star icon (★) on the World selection screen."
With the buff you'll catch up with them in a matter of one week.

The additional advantage to have the buff for a new player (in my opinion) is that in this case you get enough XP from doing only the Main Story Quest chain and Duty Roulette, so you can enjoy the story without "grind to the next level" pauses

I'd make an Arcanist as a first character as well for two reasons:
1) you level 2 jobs in the same time - a Summoner (ranged caster dps with a tanking/dpsing pet) and a Scholar (healer). Both jobs will be always on the same level, no matter which one your are playing.
2) If you can heal (scholar) you dungeon queues will become non-existent while all the solo questing you'd be able to do comfortably on the Summoner.

[MistakeNot]

I'm not sure they'll get the "Road to 60" buff after a transfer.

They won't. You only get the "Road to 60" buff when creating a new character on a New or Preferred world.