Well, the title says it all. I have done all of the dialogoue options for Arcade Gannon to gain his "trust" so he would open up to me about the quest, For Auld Lang Syne. Now, he has yet to give me it, and also, after have traveling to The Fort to kill Caesar, it seems as though he has lost his Plasma Defender and now melees. Are there any fixes for this problem?

You have to reach the point in the main quest where you get the "point of no return" message. Select the option that says you aren't ready, and Arcade should give you the quest then.

I have already done that =/ No use there.

Open the companion wheel and switch him to melee, close the wheel, now re-open it and select ranged. He should pull his gun back out. This happens to me frequently with all humanoid followers.

That's a bummer. If it makes you feel any better I can't do Raul"s quest because I had previously conversed with Ranger Andy. I hope they fix all the scripting hiccups in the next patch.