You're asking two questions that I see:
1. Can going to a lighter gauge result in buzzing? Yes, that possibility definitely exists. A string of lower tension will arc wider than a string of higher tension. Depending on your string height and neck relief (what is commonly termed "action"), you may be fine when you change gauge, or you may find you got buzz where there was none before. You can compensate for this by adjusting the action, or adjusting your attack. Only you can decide whether the overall changes are "worth it."
2. Volume changes and/or "coming alive" with a gauge change? There is a definite dynamic between a guitar top, which is the
soundboard carrying the lion's share of the guitar's intrinsic tone, and the tension it is placed under by the strings. But
generally speaking, less tension yields lower volume: by how much differs from case to case so don't take that as gospel. Further, increasing or decreasing tension on that soundboard
will affect the tone: for better or worse is your call. I don't mean that to be a cop out, but no one can predict what a given guitar top will sound like when you change the tension placed upon it. Tension, by the way, that is a designed-in parameter when being built.
Taylor's GS, Dred, and Jumbo bodies, for example, are
designed with mediums in the mix, so switching to lights will result in a deviation from its initial mission. Only the owner can decide whether said "deviation" is a plus or minus. Likewise, the GA and GC bods are designed with lights. As they say with cars, your mileage may vary.

Like which string brand, which string gauge is an integral component of the tone the guitar produces. The right string is the one that sounds and feels best to you. Though some things can be adjusted for (like the aforementioned "action"), the tonal results are what they are. And you can move on to other strings/gauges to
try and achieve what you're looking for. But whether you
can achieve it is something only you can determine after trial. Hope that helps ya a bit

Edward