As partially noted above, the standard hornet can essentially be fitted, converting it to the Ghost or the Tracker using in game parts/upgrades. It CAN NOT change into the Super Hornet with in game parts/pieces, as it is a different ship frame (twin cockpit, larger max power plant size).
Also, the twin cockpit really isn't the same as some of the other 2+ person ships. Only one person is needed to fly and fully operate the Super Hornet (same with the Caterpillar). You can, however, use that second seat for carrying another person into battle with you, which might be useful in a fleet operation where that second person can then focus on simply coordinating the attack, analyzing sensor data, calculating risk/threat assessment/calling primary targets. These are all things that will be more difficult for someone actively flying in heated combat to do since they will be focusing on trying to avoid fire, missiles, asteroids, as well as trying to position themselves to shoot back...
I would say upgrade to the Super Hornet now if you have the money for LTI. Base loadout on the Super Hornet is pretty good (especially weapons wise). You really don't need to spend anything upgrading the Super Hornet to make it a very deadly fighter. Which means you don't need to spend anything at all ever again on that ship (aside from fuel and docking fees). If it gets blown up, you get a replacement with the same base loadout again, which as I said, you don't need to change, which means you don't need to pickup extra insurance. It essentially becomes the backbone of any dangerous fleet operations in the game (good enough to do the job as well as no risk to the pilot using it).