How to level dps alts?

[MsMisato]

Is doing low level fates via Level Sync efficient?

you can also run some dungeons with squadron, though it takes practice and time to get the squad mates up to par. I am talking independent, offensive, or defensive order level. Level 4 or 5 is what you want. Once you get there you can burn through mobs pretty quick.
as for fates it depends. ARR not so much unless you are waiting for queue or something. Lvl 60-80 (StB and ShB fates are ok xp, not the best but not the worst).
Roulette all of them even frontline. Cool thing you can swap from a dps you a leveling to one you are familiar with in PvP. If anything you get some wolf marks and ok xp.
PF for a specific dungeons for leveling as I see that from time to time still.

Make sure to eat food, fc xp buff, wear xp buff equip as well.