Like is there another way to find them and do quest for them etc? The only way to get Arcade Ganon that I know of is to have 75 speech. The only reason id want Ganon as a follower is to find the remanents.

Also the only way I think I can get Rose is with speech and or barter I am pretty sure.

No other way.

You can get Arcade by getting a high reputation with the Followers.

EDIT: Thanks

Male characters with the Confirmed Bachelor perk can also recruit Gannon bypassing the speech check.

I don't think Arcade Ganon will follow you if you are with the Legion and hated by the NCR. I could be wrong?

Also i've heard if your character is "stupid" (Int <= 3) you get him as a follower without any checks?

I am Idolized by the legion and the Followers(I have received the safehouse key from the spike haired girl.) and Merciful Thug with the NCR and Arcade says no when i ask him to travel with me.

Really? So high speech or having a worthless character is the only way to get Arcade Ganon (3 int = a terrible character no skill points lol). Or have the confirmed bachelor perk

Arcade will NOT side with you if your reputation is accepted or higher with Caesars Legion.

sorry