SO .... to wrap up the poll, NONE of the options will determine the "fastest" arrival time (as you can't speed up the sound wave in a consistent medium), but certain design criteria may slow it down, such as some horn types and certain electronics (DSPs, crossovers or the appropriately named delays).
We purposefully put delays in place to make sure we have a coherent sound front arriving at listeners ears. For long rooms, a set of delay speakers placed out in the audience, will normally be delayed by the the time it would take for sound to arrive to that point from the main speakers, so they sound in unison.
For speaker enclosures that are separated (normally the subs), most DSPs and some crossovers allow for one or more of the boxes to be delayed, so again, the sound arrives at the same time. For my horn loaded subs, that's an approximate 7ms I delay the tops, since the internal horn is about 7 or so feet in total length and therefore it takes that 7ms for the sound to actually get out of the sub. By delaying the tops, it syncs everything up. Delays may be needed also if you place the subs away from the plane of the other speakers .. say at the back wall or out in front of the table. At the back wall, you may need to delay the tops if they are in front of the subs .. out front, you may need to delay the subs if they are in front of the tops. Delay is usually done at 1ms per foot of distance (actually .89ms) at normal temps/altitude, etc.
All to get a cleaner sound.
BTW, if you don't have a delay unit, I have used the Behringer Shark (DSP110) for years for a number of things like delay, feedback control and even signal level matching (mic to line or vice versa). It's a neat unit for less than $100 (I have several).