My Cleric took the Leadership feat. After working with the GM on what class/level my Cohort would be, we agreed on a 7th level Bard. The goal was to have a support Cohort that could buff and assist the party in combat situations, but not be involved (swinging a weapon) in combat.
I've never played the Bard class, and was wondering what would a bard do in combat the first 1-5 rounds to buff the party or provide battlefield control?
Inspire courage. It's the bread and butter and peanut butter and jelly of the bard class. You may occasionally want other performances, but that one's the big one. Especially with the Flagbearer feat and a Banner of the Ancient Kings, which will make it go from good to insanely good.
Spells. Bards are one of the best classes for buffing. Pick spells with that in mind and the type of bonuses they grant. At 7th level, the bard now can cast haste, for example.
I usually find that after a round or maybe two you don't need to spend any more actions on support (although being ready to stabilize a downed comrade via CLW is a good plan) and Bard don't make the best controllers, since they don't have the best spell list for it and 6 level casting means their DCs are lower than 9 level casters for their best spells and they have less of them to spend.
Usually I would recommend a Bard take a secondary roll as a striker for when they aren't buffing, but since being a cohort will make him weaker than the PCs, he probably doesn't want to wade into melee and you might have trouble with enough feats to make him a significant ranged threat.
One option is to go for dazzling display, which works well with Bard anyway (versatile performance can give you the intimidate skill) and only costs 2 feats for a good chance to demoralize all foes within 30' which is not bad battlefield control and won't use up any daily resources.
In addition, while it is a very nice effect, it is pretty quick to run and won't be overshadowing anyone which are good things to consider in a cohort.
While the Bard is not the best summoner, summons work at range and provide targets to soak up enemy attacks. Some summons also have nice SLA and SU abilities. Summons that you can talk with can be positioned to provide flanking.
Sure, they die quickly, but before that, the flanking is a buff, and the damage absorption is another kind of buff. They also get your inspire benefits.
I second using Dazzling Display. He can then grab Motivating Display and Intimidating Performance Lingering Performance can increase his bardic performance rounds per day without too much of an opportunity cost since he isn't combat focused. He can also variant multiclass Cavalier and Qualify for Battle Herald. Even if he doesn't prestige, there are some Orders with Neat Challenge bonuses and 2nd level abilities. Order of the Lion grants him a dodge bonus (helps avoid the target) and Lions call. Order of The Tome grants against spells and SLAs from his target and gives him 1/2 his level again on knowledge Arcana or Religion.