The thing is, data is an abstract concept. Without a medium, there can be no data, similar to how you can't have a drawing without something to draw on.
I really don't see why there has to be a physical medium... after all, if both classic>DASH and EXE>SSR operate on the same physics, we still have ZERO's Cyberspace, the Program World which encompasses all Substance World phenomena in the form of a program. (Different from the X/EXE cyberspace, which is ZERO4's Transfer Circuit; both the internet and physical storage mediums) ZERO3's cyberspace is a separate dimension of reality and is the space where all data inevitably ends up.
DNA Soul
DNA Soul = Repliroid's operational [mobilization/movement] DNA program = Repliroid Soul = Repli Soul = Cyber Elf = Program Life Object = Repliroid Personality Program
DNA Program
Program that makes up the characteristics of a repliroid. Zero's Learning ability utilizes this, but Axl's ability to completely copy a repliroid is rare.
DNA Soul
A repliroid's operational [mobilization/movement] DNA program that has been pulled out. It appears that Berkana took the souls from the erased repliroids and inserted them for use in the bodies of Iregulars.
Erasure
The phenomenon where a repliroid's operation program disappears all the sudden. An erased repliroid loses all consciousness, reduced to being like so much scrap iron. During the Nightmare Incident, a phenomenon similar erasure happened to Isoc.
Now, in the Classic/X/Zero-verse, the existence of a non-physical medium for the storing and retrieving of data becomes a canon fact as of the middle of the X-series, with its existence being likely from the beginning of the Reploid species. This, of course, being the DNA Soul. The events of Xtreme 2 are enough evidence to suggest that DNA souls exist in the material universe as some kind of energy-based storage medium containing the "genetic" data of the Reploid as well as their memories.[
Well, Repliroid Souls are Cyber Elves. Cyber Elves which live in Cyberspace. Cyber Elves which have bodies that are created with pure energy in the image of elves... Cyber Elves which are based on Sigma Virus... Sigma Virus is also an energy based existence that can be transmitted by radio-transmission, X/EXE cyberspace and even just move through the air itself without the use of any noticeable medium.
Sigma Virus's origin is Wily's creation of Zero and putting it inside of Zero. The Repliroid Soul has its origin with X's nearly human soul. However, Zero too has a soul like that, a Cyber Elf, hence his existence as a Biometal (Which have Cyber Elf-like abilities). Furthermore, we also can't state with certainty that robots that predate X did not have souls. Those souls might not have been as much like a human as X, but they'd be souls nonetheless.
Either way, the existence of energy-bodied programs has no importance to Kotobuki.
Kotobuki
The Gospel Server's radiation has the same effect as Zero Virus. Cyberspace materializes in the real world. This is not the ZERO cyberspace, rather, its the X/EXE cyberspace. As in, it's the internet, in a setting in which the internet can connect to nearly every single machine, wireless even. Either the data was always being transmitted wireless, or the radiation is causing it to be. I'd just like to note that by SSR's account, a true wireless worldwide connection isn't established until the Sattelite Admins appear; EM-lifeforms are responsible, before that, wireless transmission was much more similar to what the real world has.
To mention a related concept; teleportation. It's turning a material object into data and transmitting it, only to materialize it elsewhere. As ZERO4 shows, wireless transmission is used here, using the X/EXE Cyberspace. Hence, by using teleportation, a Repliroid can actually enter the X/EXE Cyberspace.
The hologram also works with Gemini Man's hatred and weakness to snakes.
Snakes possess keen non-visual senses, and it's likely that Snake Man and his Search Snakes possess IR sensors. Now, a hard light hologram likely possesses a very different infrared image than a solid Robot, and thus a snake would be able to tell which is the real and which is the fake if it is indeed holographic. As for the physical weakness...
... I'll need to think more on that. For now, all I can think of is "LOL game mechanics"
I guess with the "Search" Snake being his weakness, I guess we are indeed dealing with holograms. (Solid ones controlled by the main, mind you.) The intended function is actually that the snakes uncover the real one, hence his dislike for them. LOL game mechanics for this being improperly portrayed as just extra damage.
Schrodinger's Copy.
Combined with Schrodinger's Replacement?
In other words, LOL game mechanics.
Doesn't address if it's the orb or the big dome that's projecting the alien, but meh. ^_^
I'd say the dome is responsible for the holograms. The orb being related in some fashion to have the dome create the alien around it, with "damaging" the alien messing up both the orb and the dome.