I am strongly against Parelli's games and CAs techniques. They are physically harmful to the horse. I have seen many horses with physical issues even though they are "obedient" from doing these games. Even in their clinics, horses that they say are doing well are nervous, high headed, and eventually seem to get bitter. Judging from your absolutely adorable little pony (if you decide you don't want him, I would love to have him!), he is already a little strung out in the picture. Instead of throwing a lot of things at him that are going to make him even more vulnerable physically, I would start slow and with the basics.
A little extra info..... Horses don't like to be in charge. It is a very stressful position within the herd. However, horses don't like to feel at risk either. If they feel that they are the most well equiped within their herd, then they will assume that role. If a horse feels exceptionally at risk (I find this a lot with horses that have been through auctions or have serious physical issues) they will test their leader that much more. I worked for someone who got plenty of horses from livestock auctions. I personally find a lot of horses that go through auctions to be either very scared or very protective (seen by some as "dominant"). One pony that I own was purchased at an auction by her previous owner. I bought her a couple months later for 1/4 of what they payed for her since she was chasing people in the pasture and trying to strike at them. She is now ridden by small children, but she was "dominant" by most peoples standards when I brought her home. I didn't see her as being dominant though, I saw her as being protective of herself.
If holes are left in training, then you will always fall through them later in your program. You mentioned your pony had a problem with catching, so this is where I would start. Hopefully you have a smaller turnout paddock and you aren't using a 20 acre pasture, that might take a while. Carry a halter with you. Now, you are just going to be a pest. You don't need to run, you don't need to make him run, just walk towards him. If he walks away, just follow him. If he makes any aggressive gesture towards you, use whatever force necessary to get him out of your space. Continue following him until he stops and face you then stop immediately, looking at him directly. Now just stand there. If he looks another way, start walking towards him. If he leaves, follow along behind, if he faces you again, stop. Stand there, just looking at him, until he starts to relax. Look for the classic signs, licking and chewing, yawning, and the head dropping to or below the wither line. Once he is relaxed with you being there, approach again. Don't sneak up on him, you have nothing to hide. Place your hand square between his eyes. If he walks away, start following again. If he doesn't, go ahead and scratch his body, rub him a little, and while you still have his full attention, walk away. Repeat this daily and you will find it doesn't take long at all before he will start coming to "catch you" when he sees you at the gate.
I have caught feral horses this way as well as horses with "respect" issues and horses that just had their experience with people and found it wasn't all that great. One horse was an untouched 3 yr old with a baby at her side. She had never had a halter on her. It took me about 3 weeks of doing this 4-5 times a week. Then everything else just came quickly. She already knew how to stand for grooming from all the time I spent rubbing her, within 2 weeks of being in a stall she had all 4 feet trimmed without a glitch (had never even been picked up before), and she started lunging easily shortly after.
A lot of people find this boring, they want to see horses do things and see things get done. As boring as it may seem, I have found that it is the fastest way to get there.