New account

I have a friend who is wanting to get into the game. He got Ayala as his first char which in my opinion wasn't to bad (was wondering if he should try over). Right now he is level 18 and sitting 500 in arena but as more gets unlocked including guilds who is worth going after first? Qgj from cantina while farming gs or lando. Biggs or lumi from gw? Worth getting Rey? Or who should he focus on from guild shipments? Any other info I could send on would be greatly appreciated thank you!