You'd then be carrying a weapon in your shield hand, which I believe would negate the AC bonus. The description of Bucklers indicates you lose the bonus when you use your shield hand, which I believe includes holding a torch or lantern, or a weapon, or just about anything. You'd have to check with your GM regarding their definition of use.
It looks good.
If you can hold and use something as large as a bow without penalty AND without losing your shield bonus, you're fine.
Paizo really needs to clarify/rework the differneces between the differnet types of Shields.
Currently Light Shields really have no reason for existing, besides some exotic shieldbashing builds.
Its like there is one step missing on the stair for "heavy-ness" of Shields. Where you have a trade-off between ease-of-use and AC.
I've always felt a bit lost on shields and somatic components (and fiddling with holy symbols). I didn't even remember seeing that tossing a spell while bucklered would mean no shield bonus for the round. I think this is why I've leaned towards just outright melee smashers lately. (That and they're fun.)
So can you toss spells with a light shield? Or wield the symbol? What's a cleric doing when she or he is juggling all that stuff? I know it's explicitly in the FAQ that you don't have to worry about your two-handed weapon when casting, so a cleric with a longspear is fine ...
A buckler says you can use the hand you are wearing it on to cast spells with somatic components, but you lose the shield bonus to AC until your next turn.
Is there anything to prevent you from moving a weapon in your other hand to the buckler hand, since the buckler expressly leaves your hand free, and then use your free hand(the one without the buckler) to cast the spell, then pass your weapon back to its original hand? Is this a valid way to use a buckler and carry a weapon, and cast somatic spells without ever losing the buckler's shield bonus?
I suspect this would run afoul of the unwritten 'metaphorical hands' rule.