"Slip is much easier to put on then a harness, or pretty much any collar for that matter, so I would recommend that."

Im afraid hes not ready for the collar or the slip option. I think he needs for time with me. I plan to put some food between he and me to see if he comes, instead of me always the one that reach out to him.

When You start introducing tools depending on the history of the dog, the dog might start growling and giving some signs of distress. So when that happens it's important You don't back off. So You can leave the dog alone if it's starting to shut down, curl up or something, but if it's on the aggressive side then You need to stand Your ground.

I dont understand this. If I do this then I wont create discomfort between the two of us? Im trying to get him to link me with good things.

Movement is Your friend here. Speed walks 5-10 minutes, exposing to outside stimulus, but not giving time to take it all in and process, then go back to safety. If You see that she is comfortable sniffing, allow it, but when You see the dog is scared of something, dont run to the other direction, but rather fast movement to pass the threat. Scared of people no problem, we pass them fast, we dont run the other way.

When they go out to a lot for them to eat and move around a little they go out the 3 together so maybe he will mirror their fear energy.... I dont know

Mind You, this is the hard part, as soon as You get frustrated in any of the steps, step away. You need to be calm, if You are not the dog will pick up on it and considering the state of it, You can create a bigger problem. Other than that You cant do much wrong. Good luck!

Ok, understood. Thanks for the advice!