https://pathofexile.gamepedia.com/MasterYeah it is. There is no best master, ofc some of masters are a bit easier to level. But just pick up one hideout u like most. That's how I do.
Master level 5 u can upgrade ur hideout to medium and invite 4 masters in ur hideout
Master level 7 u can upgrade ur hideout to large and invite 7 masters (all) in ur hideout
Zana , Leo, Navali does not count towards to mster limit