I have 17 speech, and wiki wasn't exactly specific..But I can possibly make Gannon go back to the followers afterward his quest and receive his armor correct? I rather not kill him.

If you convince Arcade to go back and stay with the Followers, rather than fight with the Remnants, he will leave for a while, and appear after you leave the Remnants bunker and give the Gannon family Telsa armor to you. (Note that there is an 80 speech check if you try to convince him to do something that contradicts the answers you gave during For Auld Lang Syne.) - Wiki

What it says sounds quite clear to me,
1. Tell him to back to freeside
2. Speak to him with a speech skill of 80
3. ???
4. Profit

Yeah I ended up doing the quest without 80 speech and got him to go back to freeside and he gave me his armor.