I'm skeptical of this, too be honest.
First of all, there are a lot of things mentioned in prior posts to mine that point out a lot of very valid things.
Christmas is a little more than 20 days from now, and it is approaching quickly. If the app is going to be done by Christmas, he should be able to post screenshots, or some kind of legitimate information about the app. It's been a day or two, if not more since he said he needed to contact his "assistant". If his assistant is so hard to reach he still hasn't been able to reach him yet, how have they been working on the app? And who is this assistant? If they are only your assistant, from what you've clued us in on, why are they in control on app screenshots?
As far as I am aware, the OP (Jippohoon) does not at all mention his experience with coding, and scripting apps of any kind, so we are immediately to question the apps stability. According to his profile, he is 19, which doesn't mean he couldn't have taken online courses, high school courses, or even taught himself how to code and script, but it is impossible for him to have gone to college and learned anything at that type of schooling level. Now,t hat doesn't exactly mean anything, seeing as our very own Forarain taught himself code (from what I know) however, that is not the same as the coding needed to develop an app, and from what I know, that coding is even harder. I do not OP's abilities, however this is a very difficult task.
Lastly, as far as I know, this cannot legally be placed on an App Store and called "MCSG official forums" without consent from the person who owns the trademark, or "business" of MCSG. I also know that putting an app on the App Store requires a developers license type thing registered through Apple, and it costs money to place said app on the App Store. Without a real degree in developing, or whatever you would call that, or any legitimate experience you cannot legitimately acquire the needed developers account to place an App in the App Store.
However, with all of that said, it does not need to go on the App Store, but that leaves the question- then how will we download this app? As far as I know, it is possible to download apps from other sources on your device, but all this I know only from using a Pokemon emulator, which is no where near the same. It is possible, however, to develop a website redirection and then place a "shortcut" on your home screen, however that is not really an app, it is a shortcut to a website, which essentially is over-complicating what you could do just by connecting to the normal website.
And even then, that's not legal, or allowed without consent from Chad himself because that'd be like making your own Nike website, but giving it a different layout without having permission from the owner of Nike. This is the same, just on a smaller scale.
Even still, with my skepticism, I am anticipating seeing what comes out of this. I would love to see an MCSG iOS app, however, at this time with the current proof you've given me, I do not believe it will be this.
I still do believe you can do it, but this is what I need to know from you-
A. How do you plan on distributing this app? The App Store should basically be out of question, unless... (see question B.)
B. Do you have any legitimate developing experience? Could we see your past projects?
C. Screenshots. Legitimate, in-app screenshots would be the holy grail to your success, and having people believe you.
D. Who are you working with, and can you answer question "B" about them? What have they developed in the past? Currently all we know about them is that they are unnamed, and simply referenced as your "assistant" meaning they are not the main face of this project, but they still help you along.
E. How do you plan to get permission to continue with this distribution of this app? From my prior knowledge, you cannot simply redesign the website with permission from the company owner.
Well, there's my opinion

Like I said, I do not fully doubt you, and if this is real, go for it- good luck, however I'd really like to see some proof that this is real
EDIT: After a bit of digging done by my friend, it appears you are banned, and definitely not in very good standing with Chad, which will make getting permission for things very difficult.
http://i.imgur.com/qepVoGH.png
http://i.imgur.com/FPh0528.png