Heroic Echoes doesn't work with supernatural abilities (like bards inspire courage), so that might not be the best option. It works on spells, spell-like abilities, and magic items. So, not even the moral bonus from a rage ability is effected (though a rage spell would be). You are better off using actual spells that offer morale bonuses.
Ideally you want spells which affect multiple targets and give a morale bonus. There aren't that many of those; bless and fiendish rage are the best that fit, and they're not on the same spell list for any class. But...bless is on a number of lists which can be added to a base class spell list.
So, a psychic with the faith discipline, VMC imperious sorcerer could work. You won't get a lot of feats but the encouraging spell metamagic may well be worth getting once you can (L9). L1 and L5 might be spell focus and spell specialization, or persistent spell and blissful spell, or any other pair of feats you like on a spellcaster.
Traits? If you go for metamagic then metamagic cost reduction might be useful, if you want to make the most of the diplomacy bonus then the traits which make social skills int-based might be worth taking, or whatever - traits make very little difference and can be applied to whatever you find shiny without reducing the effectiveness of your character.