
Faolán Maiali the Azure Abjurer |

So I'm playing a kitsune bard who sings and plays a hurdy gurdy, and the GM decided to introduce a homebrew multiclassing rule (via plot device) that basically functions like a subclass.
The rules for the multiclass are as follows:
You have your main class (and other multiclassing) which you take levels in normally.
Then you have your subclass:
You gain the class features, class skills, spellcasting ability, and weapon and armor proficiencies of your subclass, but you don't gain the BAB, saves, HD, or skill points of the subclass. Your effective class level for gaining class features and spellcasting is otherwise equal to half your actual HD (including caster level).
As of right now, my bard is only 2nd-level, so he isn't quite filled out in terms of his combat niche, but I had intended to make him as bard-y as possible, prioritizing performance and support over other combat skills, his first level feat being Lingering Performance. He also acts as the party's rogue of sorts, since he has Disable Device as a class skill from the Vagabond Child trait.
His ability scores are currently: Str 10, Dex 21, Con 16, Int 18, Wis 13, Cha 19 (The ability scores are higher than usual because the GM called for 30 Race Point characters).
The problem: I'm having trouble coming up with possible classes that would work well with a bard (archetypes are allowed for subclasses).

Lelomenia |
I guess here casters aren’t so exciting with the poor spellcasting advancement and full BAB classes aren’t exciting when they...don’t get their BAB or d10 hp.
I think Rogue (possibly Ninja, to be more specific, because Vanishing Trick) might actually provide good value here, sneak attack dice and extra talents every 2 (so four) levels.

VoodistMonk |

What type of Bard are you... do you have an archetype?
Brazen Deceiver Bard, with Charlatan/Guild Agent Rogue as your subclass... you can literally lie to anyone about anything... and they will believe it, and tell others... and others will believe them because people you lie to use your bonus when they spread your lies...
For Rogue Talents you will want Obfuscate Story, Steal Story, and Convincing Lie... you get Black Market Connections and Rumormonger for free... and the Gossip Collector Vigilante Talent for free, too...
At level 11, your Deceptive Tale Performance applies to Impossible Lies... it's over... you now run the narrative with your lies...
For feats, grab Persuasive, Confabulist, and Rhetorical Finish... wait for the GM to ask you to politely GTFOH...
These aren't the droids you're looking for, type stuff.
Who? Me? Wrong guy, guardsman. Get lost.
Salesman: Hey, give that back!
You: But I already paid you for it...

Faolán Maiali the Azure Abjurer |

What type of Bard are you... do you have an archetype?
Just playing a normal, vanilla bard. No archetype.
Skill ranks were placed in:
Acrobatics
Disable Device
Knowledge (assorted)
Perception
Perform (sing and string)
Spellcraft
Stealth
Use Magic Device
I chose string for Versatile Performance to get Bluff and Diplomacy, coupled with the Savant social trait to further boost Perform (string) by +2.
Personality-wise, he's a curious and gregarious party-pleaser. The cheerful go-getter who proactively takes care of all the arrangements when arriving in a new town; gathering rumors, arranging inn accommodations, that sort of thing.

avr |

Hurdy-gurdy; he really doesn't have hands free with an instrument he won't want to drop on a battlefield and may even be playing every round. That rules out martial stuff to me including sneak attack. And most spellcasters. Maybe a psychic spellcaster - a medium can buff with shared seance and with their psychic spells, or a mesmerist can debuff and cast spells similarly. Possibly one of the cha-based monks - nornkith (original) or scaled fist (original or unchained) since monks don't need a hand free to fight.
Edit: There's an obscure class called the omdura which Paizo made for a particular setting. If available it's basically an inquisitor who can share their judgements, but who takes a standard action rather than a swift to start them. Doing so shouldn't require free hands. It's on d20pfsrd but not AoN.

VoodistMonk |

Alchemist of some sort... I do enjoy the Ectoplasm Master combined with Reanimator, personally. Anyways, grab Vestigial Arm (×2) and Wings... getting those three Discoveries will take 12 levels at half speed progression on the subclass. But now you can play your hurdy-gurdy and have two hands free, and do it all whilst hovering out of melee range.

Faolán Maiali the Azure Abjurer |

Hurdy-gurdy; he really doesn't have hands free with an instrument he won't want to drop on a battlefield and may even be playing every round. That rules out martial stuff to me including sneak attack. And most spellcasters. Maybe a psychic spellcaster - a medium can buff with shared seance and with their psychic spells, or a mesmerist can debuff and cast spells similarly. Possibly one of the cha-based monks - nornkith (original) or scaled fist (original or unchained) since monks don't need a hand free to fight.
Edit: There's an obscure class called the omdura which Paizo made for a particular setting. If available it's basically an inquisitor who can share their judgements, but who takes a standard action rather than a swift to start them. Doing so shouldn't require free hands. It's on d20pfsrd but not AoN.
Mesmerist might be a possibility, what with the racial bonus to enchantment save DCs, the class's gaze, and so forth. Could be a great complement for his spellcasting abilities, especially if the chosen Mesmerist spells don't scale much with CL.
I was also considering maybe Unchained Rogue (with Kitsune Trickster archetype), or maybe even some form of Swashbuckler (maybe Inspired Blade), since the latter uses Cha for a lot of their class features, though Unchained Rogue would ultimately be far better for damage output.
As for the hand limitation problem, since he has equal ranks in both singing and string, he can maintain by singing when need be, or eventually get his hurdy gurdy enchanted so the crank operates itself on command. Or even a limited use magic item (like a uses per day item or a wand) that casts unseen servant, which would work great for most of an excursion since it lasts for 1 hour/level.
Regarding the alchemist suggestion, we do already have one in the party as a primary class, so I'd prefer to avoid any overlap there.