I do have one question though..how exactly do I get him to stop trying to suckle on my other male cat? Is it because he wasn't weaned off his mother? seeing as though he was only very little or is it something that soothes him?

What a pretty little kitty and fabulous photo resting on the keyboard, LOL! Patience paid off in the end, to everyone's benefit. Well done!

Your little guy looks like Monty when he was small. I caught him by my house at about eight weeks. He also was wild, hissing at me, trying to bite and scratch. I'm constantly amazed at how that once terrified wild animal is now the boss in our house. He actually scolds me if I don't get his food quickly enough or take him outside when he wants to go out. (He's not allowed out without supervision.) Yesterday I left very early and got home very late from work and Monty's loud, persistent meowing left no doubt as to how he felt about that! Though I was exhausted I had to spend some time outside with him last night. Some tuna with his breakfast today seems to have smoothed things over.

Well done for domesticating that feral kitten.
As Michael already said, you probably saved his life !
It's amazing how even tiny feral kittens have the instinct to hiss at people and mistrust them, to protect themselves.
It was his lucky day when you took him in.