The Enclave did a lot of bad things, but there were good people at Navarro. Good people with a lot of experience. Not many of them are alive anymore, but I think they could make a difference in the fight against Caesar.
The Enclave Remnants are what remains of the now defunct West Coast Enclave, which was nearly destroyed due to the destruction of the Enclave Oil Rig by the Chosen One in 2242. While others went east to Chicago, the Capital Wasteland, and other places according to Arcade Gannon, there were a few that chose to stay and they soon earned their namesake of Enclave Remnants. The few known survivors all reside in the Mojave Wasteland.
If the player chooses to ask them to side with the NCR, Orion Moreno leaves the room. He is found just outside the briefing room in the hangar. He will talk about his hatred of the NCR and will refuse to fight for them. If the player has a Speech skill of 80 or a large amount of NCR infamy, Orion can be convinced to participate in the attack, but otherwise he will attack the player and must be killed.
If the player asks them to side with the Legion, Cannibal Johnson and Arcade Gannon will leave and there is no way to convince them to stay. The player can then talk to Orion Moreno for training in power armor. Moreno will give the player Johnson's suit since he won't be using it.
In order to make an alliance between the Remnants and Yes Man or Mr. House, you must convince them to fight for NCR, since the path and ultimate goal (killing Lanius) are still the same. However, Cannibal Johnson will turn hostile if the PC can not talk down General Oliver.
Despite surviving the destruction of the oil rig and the loss of their comrades at Navarro, the venerable Remnants were no match for the Courier. They carried the secrets of their old lives to their graves.
After their bold arrival at Hoover Dam, the Remnants disappeared as quickly as they came. Legends of their power spread throughout the southwest, a reminder of why people once feared the sight of vertibirds in the sky.
Merciless in their assault on the NCR, the Remnants struck fear into the hearts of even the centurions at Hoover Dam. Well aware of the full extent of their power, Caesar commanded his troops to not pursue them.
Complete the quest For Auld Lang Syne, convince Remnants to aid the Legion, complete the quest Veni, Vidi, Vici for Caesar's Legion with Caesar alive.
Merciless in their assault on the NCR, the Remnants struck fear into the hearts of even the centurions at Hoover Dam. Caesar's heirs aggressively pursued the Remnants into Arizona, losing hundreds of legionaries in the process and gaining nothing in return.