My main assessment would tell me that you are getting ahead of yourself. He is not ready for longeing because he does not have enough respect for you or for that lead-rope yet.
I would spend a week on the ground without asking him to go forward more than a step or two. If he is rearing now, he will rear doing other groundwork (or while tied) and that will give you the opportunity to 'effectively' correct him or let him correct himself.
It is my contention that every new thing you do with a horse -- every new lesson -- the horse should be so well prepared and so ready for it that he does it like he has done it before. When you can go from step to step without a single glitch, you know that you are not skipping steps and creating 'holes' that the horse will leap through when asked to do more.
You skipped doing enough mannering on the ground to get his respect and teach him to move and only move on your command.
My ground work that leads up to longeing is this:
1) A horse must be well-trained to lead. He must respect a halter. Do this first.
2) At my house, he must be trained to tie solidly for hours at a time. (I can about guarantee that this horse will rear up and will fight being tied.) Let him work it out there and not fighting you. It is a waste of my time to argue with a horse that has not learned to stand quietly and relaxed as long as I want him to stand tied. They ALL have to 'give it up' before I go any farther.
3) When a horse comes out of the pasture or barn, will stand tied quietly (resting a hind foot), I will start to work with him. I start out by leading a horse 3 or 4 steps forward, I stop him, face him and say "Whoa!" Then, I take as long as it takes to teach him that when I face him and say "Whoa!", I mean for him to do just that. If he has learned to stand well while tied, it takes about 5 minutes to have him where I can walk all around him, brush him, straighten out is tail, stand 10 feet out in front of him (facing him) and he will stand very still. He will do this because he is ready to learn how to stand still.
4) When he has learned to stand quietly tied, I will 'sack him out' with a long, soft cotton rope. This gets much of the 'reactiveness' out of a green colt. I do not do much sacking out with a blanket or sack while a horse is tied. I do that in hand. But, I sack every one of them out with the big soft rope. I want the 'kick' and the 'jumpyness' out before I even groom one.
5) Then, I take him 'in hand' and I teach him to back up and to move his shoulders over each direction. [This is MUCH more important than yielding his hind quarters and is much more difficult to teach and leaves a much bigger hole in a horse's training if you skip it. ] This lesson is not over until he steps back lightly and willingly and moves over willingly with just a touch and a smooch.
6) Then, I teach him to move his hind quarters away when I ask with a smooch. Just as importantly (maybe more so), I teach him to stand and NOT move away from me until I ask him to.
7) I will still not let a horse work going forward until he does all of this with patience and great manners. If he takes a single step toward me, I will back him up 10 steps and turn him around once or twice to the right (turn on the haunches) and give him another chance to take a step toward me if he dares.
Since this horse already has reared at a handler, he may do it again, even after learning to stand tied. If he does, he needs to be roughly made to back up at least 10 or 20 steps.
I have had horses come to me that were already spoiled and so aggressive that it was not safe to get in their face and make them back up. In that case, I will have a second person, on the other side of the arena fence, (pipe and cable) hold a 2nd lead-rope. That 2nd person keeps me safe. I can jerk a lead-rope as hard as I want and as many times as I want until the horse decides to back up -- at which time I stop asking and step away. I will find a safe way to make ANY horse I handle 'give ground' to me when I want it to. Until this is done, no horse is safe to go on to the next lesson. To be in charge and be at the top of any horse's 'pecking order', that horse has to give ground at the slightest request. Any time a defiant horse 'bows up' and refuses to back up, HE IS IN CHARGE. That is what I see in this horse.
8) If ALL of the above is accomplished, it is a very simple matter go get a horse to walk or jog forward with just a smooch and a wave of the arm on a longe line. A horse will let you pull him around and stop him any time you want him to. A horse will do it like he has done it before.