-not very confident
I plan on short lunging sessions, some ground driving, taking him for walks off the property until he is secure enough to be ponied, and riding for 20 - 30 minutes at mostly a walk with some transitions, figure eights, neck reigning exercises, and leg yielding.
Any other suggestions to help boost his confidence would be great!
Overweight can be fixed fairly simply. Look at his diet; if there is something that he doesn't really need right now then slowly cut it back. If he's on straight grass, perhaps get him into a turn out rotation (inside part of the day, outside another part of the day) or a grazing muzzle.
Then you know with exercise, weight will slowly go down as long as he isn't getting over-fed. So that one should be fairly easy to handle. Communicate with your vet and maybe run tests if he's not losing it easily (weight-tape him and write it down for a month or so in order to keep track of his progress!) incase he has some underlying problems.
Spooky comes with a horse due to their flight instinct. You need to gain their confidence and respect by setting boundaries, teaching them to look to YOU for instruction when in the presence of a scary object, and again.. look at the diet and make sure you aren't feeding them a diet full of sugar.
Depending on the severity of the spooking, it may be a good idea to spend some extra time desensitizing them and "sending" them as you planned.
Confidence is going to be a little drawn out. In order for a horse to gain confidence, they have to FEEL as if they are able to do as you ask without hesitation or fear. Praising at appropriate times will help a horse to retain confidence that they have gained from working on something challenging and succeeding with baby steps. So if a horse isn't confident at the canter, and you canter for 3 strides and it's wonderful.. and you praise them, they will slowly gain confidence in their abilities.
It sounds phooey, but that's how it is.
They also gain confidence from their leader: YOU. If you are confident and trusting in them, they will slowly build up confidence too. And in turn will trust you.
Herd bound is also something that will take some time. To me, a herd bound horse doesn't think of you as their herd leader. They feel insecure away from their group or they think of THEMSELVES as the herd leader and fuss over their herd too. So you get the flighty herd bound or the aggressive herd bound.
How I deal with herd bound is make them feel good around me and safe. When we get to their herd and they act out, I make them work. Right then and there. I correct any aggressive or rude behavior and allow them to 'be' when they are being respectful.
ALL of these problems will be resolved if you are a herd leader.
That's the bottom line.
With respect for YOU, and trust for YOU, all these problems will go away. You must be consistent, corrective, supportive, and you MUST SET BOUNDARIES. You will be tested, you will be challenged, and it will frustrate you to no end but you must control your emotions.
Your plan is wonderful; but I would do more ground work before you lunge, drive, or ride. You need to establish your relationship with this horse or you leave it with too much to decide and you end up with serious problems that will only escalate. With horses you must be clear and direct. Mix every session up to keep their focus and interest. But work on leading; following your body language as you halt, back up, turn, etc. because this will help the horse learn he needs to follow you. And do the same without the halter on (but be careful.. make sure you trust this horse first and he trusts you)
Hope I helped.